1978 

National Cancer Institute 

CARCINOGENESIS 

Technical Report Series 

NO. 80 

BIOASSAY OF 

1,4-DIOXANE 

FOR POSSIBLE CARCINOGENICITY 

CAS No. 123-91-1 

NCI-CG-TR-80 

U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE 

Public Health Service 

National Institutes of Health 

BIOASSAY OF
 

1,4-DIOXANE
 

FOR POSSI-BLE CARCINOGEN ICITY
 

Carcinogenesis Testing Program
 

Division of Cancer Cause and Prevention
 

National Cancer Institute
 

National Institutes of Health
 

Bethesda, Maryland 20014
 

U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
 

Public Health Service
 

National Institutes of Health
 

DHEW Publication No. (NIH) 78-1330
 

BIOASSAY OF
 

1,4-DIOXANE
 

FOR POSSIBLE CARCINOGENICITY
 

Carcinogenesis Testing Program
 

Division of Cancer Cause and Prevention
 

National Cancer Institute
 

National Institutes of Health
 

FOREWORD: This report presents the results of the bioassay of
 

1,4-dioxane conducted for the Carcinogenesis Testing Program,
 

Division of Cancer Cause and Prevention, National Cancer
 

Institute (NCI), National Institutes of Health, Bethesda,
 

Maryland. This is one of a series of experiments designed to
 

determine whether selected environmental chemicals have the
 

capacity to produce cancer in animals. Negative results, in
 

which the test animals do not have a greater incidence of cancer
 

than control animals, do not necessarily mean that the test
 

chemical is not a carcinogen, inasmuch as the experiments are
 

conducted under a limited set of circumstances. Positive results
 

demonstrate that the test chemical is carcinogenic for animals
 

under the conditions of the test and indicate that exposure to
 

the chemical is a potential risk to man. The actual
 

determination of the risk to man from animal carcinogens requires
 

a wider analysis.
 

CONTRIBUTORS; The bioassay of 1,4-dioxane was conducted by the
 

Illinois Institute of Technology Research Institute (IITRI),
 

Chicago, Illinois, initially under direct contract to NCI and
 

currently under a subcontract to Tracer Jitco, Inc., prime
 

contractor for the NCI Carcinogenesis Testing Program.
 

The NCI project officer was Dr. R. R. Bates1'2. The project
 

director was Mr. A. Shefner^. Dr. M. E. King^ was the principal
 

investigator for this study, and Dr. P. Holmes^ assembled the
 

data. Mr. T. Kruckeberg^ and Mr. K. Kaltenborn^ were in charge
 

of animal care.
 

o
 Pathologic examinations were performed by Dr. A. R. Roesler-3

.
 

Histopathologic examinations were carried out by Dr. D. A.
 

iii
 
Willigan^, who also prepared the interpretive pathology summary
 

included in this report.
 

Animal pathology tables and survival tables were compiled at EG&G
 

Mason Research Institute^. The statistical analyses were
 

performed by Dr. J. R. Joiner^ and Ms. P. L. Yong"., using methods
 

selected for the bioassay program by Dr. J. J. Gart^. Chemicals
 

used in this bioassay were analyzed under the direction of Dr. A.
 

Gray^, with the assistance of S. Cepa-^ and V. DaPinto-^. Further
 

analyses were conducted under the direction of Dr. E. Murrill .
 

The results of the analytical work were reviewed by Dr. S. S.
 

Olin". The structural formula for the chemical was provided by
 

NCI.
 

This report was prepared at Tracer Jitco^ under the direction of
 

Dr. Marshall Steinberg, Director of the Bioassay Program; Dr. L.
 

A. Campbell, Deputy Director for Science; Drs. J. F. Robens and
 

C. H. Williams, toxicologists; Dr. G. L. Miller, Ms. L. A. Waitz,
 

and Mr. W. D. Reichardt, bioscience writers; and Dr. E. W. 

Gunberg, technical editor, assisted by Ms. Y. E. Presley and 

Ms. P. J. Graboske. 

The statistical analysis was reviewed by members of the
 

Mathematical Statistics and Applied Mathematics Section of NCI':
 

Dr. John J. Gart, Mr. Jun-mo Nam, Dr. Hugh M. Pettigrew, and Dr.
 

Robert E. Tarone.
 

The following other scientists at NCI were responsible for
 

evaluating the bioassay experiment, interpreting the results, and
 

reporting the findings: Dr. Kenneth C. Chu, Dr. Cipriano Cueto,
 

Jr., Dr. J. Fielding Douglas, Dr. Dawn G. Goodman, Dr. Richard A.
 

Griesemer, Dr. Harry A. Milman, Dr. Thomas W. Orme, Dr. Robert A.
 

Squire^, Dr. Jerrold M. Ward.
 

iv
 
1

Carcinogenesis Testing Program, Division of Cancer Cause and
 

Prevention, National Cancer Institute, National Institutes of
 

Health, Bethesda, Maryland.
 

2

Now with the Office of the Commissioner, Food and Drug
 

Administration, Rockville, Maryland.
 

3

1IT Research Institute, 10 West 35th Street, Chicago, Illinois.
 

4

Donald A. Willigan, Inc. , Research'Pathology Offices, 309 East
 

Second Street, Bound Brook, New Jersey.
 

5

EG&G Mason Research Institute, 1530 East Jefferson Street,
 

Rockville, Maryland.
 

6

Tracer Jitco, Inc., 1776 East Jefferson Street, Rockville,
 

Maryland.
 

7

Mathematical Statistics and Applied Mathematics Section,
 

Biometry Branch, Field Studies and Statistics, Division of
 

Cancer Cause and Prevention, National Cancer Institute, National
 

Institutes of Health, Bethesda, Maryland.
 

8

Midwest Research Institute, 425 Volker Boulevard, Kansas City,
 

Missouri.
 

^Now with the Division of Comparative Medicine, Johns Hopkins
 

University, School of Medicine, Traylor Building, Baltimore,
 

Maryland.
 

v
 

SUMMARY
 

A bioassay of 1,4-dioxane for possible carcinogenicity was
 

conducted by administering the test chemical in the drinking
 

water to Osborne-Mendel rats and B6C3F1 mice.
 

Groups of 35 rats and 50 mice of each sex were administered
 

1,4-dioxane at concentrations of either 0.5% or 1.0% (v/v) in the
 

drinking water. Because of variations in intake of water, the
 

doses of test chemical received by the high-dose groups were not
 

precisely twice those received by the low-dose groups; in the
 

male mice, the high dose was only slightly greater than the low
 

dose. The rats were dosed for 110 weeks and the mice for 90
 

weeks. Matched controls consisted of 35 untreated rats and 50
 

untreated mice of each sex. All surviving rats were killed at
 

110-117 weeks and all surviving mice at 90-93 weeks.
 

The mean body weights of the rats and mice were not consistently
 

affected by the administration of dioxane. Survival rates of the
 

dosed groups of rats and female mice were lower than those of
 

corresponding control groups, but sufficient numbers of animals
 

were at risk for development of late-appearing tumors.
 

In rats, the incidence of squamous-cell carcinomas of the nasal
 

turbinates was statistically significant in tests for doserelated trend in females (P = 0.008) and for direct comparison of
 

high-dose with matched-control males (P < 0.001) and direct
 

comparison of dosed with control females (P _<_ 0.003) (males:
 

controls 0/33, low-dose 12/33, high-dose 16/34; females:
 

controls 0/34, low-dose 10/35, high-dose 8/35). In the females,
 

but not in the males, the incidence of hepatocellular adenomas
 

was significant (P <_ 0.001) in tests for dose-related trend and
 

for direct comparison of both low- and high-dose groups with
 

controls (controls 0/31, low-dose 10/33, high-dose 11/32).
 

In both male and female mice, the incidence of hepatocellular
 

carcinomas was statistically significant (P £ 0.001), both in
 

tests for dose-related trend and direct comparison of both dosed
 

groups with controls (males: controls 2/49, low-dose 18/50, highvii
 
dose 24/47; females: controls 0/50, low-dose 12/48, high-dose
 

29/37). The incidences remained significant when hepatocellular
 

adenomas were combined with hepatocellular carcinomas.
 

It is concluded that under the conditions of this bioassay,
 

1,4-dioxane induced hepatocellular adenomas in female Osborne-


Mendel rats. 1,4-Dioxane was carcinogenic in both sexes of rats,
 

producing squamous-cell carcinomas of the nasal turbinates, and 

in both sexes of B6C3F1 mice, producing hepatocellular 

carcinomas. 

viii
 
TABLE OF CONTENTS
 

Page
 

I. Introduction 1
 

II. Materials and Methods 3
 

A. Chemical , 3
 

B. Dosage Preparation 4
 

C. Animals 4
 

D. Animal Maintenance 4
 

E. Designs of Chronic Studies 5
 

F. Clinical and Pathologic Examinations 6
 

G. Data Recording and Statistical Analyses 9
 

III. Results -Rats 15
 

A. Body Weights and Clinical Signs (Rats) 15
 

B. Survival (Rats) 15
 

C. Pathology (Rats) 18
 

D. Statistical Analyses of Results (Rats) 21
 

IV. Results - Mice 25
 

A. Body Weights and Clinical Signs (Mice) 25
 

B. Survival (Mice) 25
 

C. Pathology (Mice) 28
 

D. Statistical Analyses of Results (Mice) 30
 

V. Discussion. 33
 

VI. Bibliography 37
 

APPENDIXES
 

Appendix A Summary of the Incidence of Neoplasms
 

in Rats Administered 1,4-Dioxane in
 

the Drinking Water 39
 

Table Al Summary of the Incidence of Neoplasms
 

in Male Rats Administered 1,4-Dioxane
 

in the Drinking Water 41
 

ix
 
Table A2
 

Appendix B
 

Table Bl
 

Table B2
 

Appendix C
 

Table Cl
 

Table C2
 

Appendix D
 

Table Dl
 

Table D2
 

Appendix E
 

Page 

Summary of the Incidence of Neoplasms 

in Female Rats Administered 1,4-Dioxane 

in the Drinking Water 45 

Summary of the Incidence of Neoplasms 

in Mice Administered 1,4-Dioxane in 

the Drinking Water. 49 

Summary of the Incidence of Neoplasms 

in Male Mice Administered 1,4-Dioxane 

in the Drinking Water 51 

Summary of the Incidence of Neoplasms 

in Female Mice Administered 1,4-Dioxane 

in the Drinking Water 55 

Summary of the Incidence of Nonneoplastic 

Lesions in Rats Administered 1,4-Dioxane 

in the Drinking Water 59 

Summary of the Incidence of Nonneoplastic 

Lesions in Male Rats Administered 

1,4-Dioxane in the Drinking Water 61 

Summary of the Incidence of Nonneoplastic 

Lesions in Female Rats Administered 

1,4-Dioxane in the Drinking Water 66 

Summary of the Incidence of Nonneoplastic 

Lesions in Mice Administered 

1,4-Dioxane in the Drinking Water. 73 

Summary of the Incidence of Nonneoplastic 

Lesions in Male Mice Administered 

1,4-Dioxane in the Drinking Water. 75 

Summary of the Incidence of Nonneoplastic 

Lesions in Female Mice Administered 

1,4-Dioxane in the Drinking Water.. 78 

Analyses of the Incidence of Primary 

Tumors in Rats Administered 

1,4-Dioxane in the Drinking Water 83 

x
 
Table El
 

Table E2
 

Appendix F
 

Table Fl
 

Table F2
 

Table 1
 

Table 2
 

Figure 1
 

Figure 2
 

Figure 3
 

Figure 4
 

Analyses of the Incidence of Primary
 

Tumors in Male Rats Administered
 

1,4-Dioxane in the Drinking Water
 

Analyses of the Incidence of Primary
 

Tumors in Female Rats Administered
 

1,4-Dioxane in the Drinking Water
 

Analyses of the Incidence of Primary
 

Tumors in Mice Administered
 

1,4-Dioxane in the Drinking Water
 

Analyses of the Incidence of Primary
 

Tumors in Male Mice Administered
 

1,4-Dioxane in the Drinking Water
 

Analyses of the Incidence of Primary
 

Tumors in Female Mice Administered
 

1,4-Dioxane in the Drinking Water
 

TABLES
 

Design of Chronic Studies of
 

1,4-Dioxane in Rats
 

Design of Chronic Studies of
 

1,4-Dioxane in Mice
 

FIGURES
 

Growth Curves for Rats Administered
 

1,4-Dioxane in the Drinking Water
 

Survival Curves for Rats Administered
 

1,4-Dioxane in the Drinking Water
 

Growth Curves for Mice Administered
 

1,4-Dioxane in the Drinking Water
 

Survival Curves for Mice Administered
 

1,4-Dioxane in the Drinking Water
 

Page
 

. 85
 

. 92
 

. 97
 

. 99
 

,103
 

. 7
 

. 8
 

. 16
 

. 17
 

, 26
 

. 27
 

xi
 

I. INTRODUCTION

 

1,4-Dioxane (CAS 123-91-1; NCI C03689), a dimer of ethylene
 

oxide, hereinafter called dioxane, is used extensively as an
 

industrial solvent for lacquers, varnishes, paints, plastics,
 

dyes, oils, waxes, resins, and cellulose acetate and as an
 

inhibitor in chlorinated solvents (Stecher, 1968; Stanford
 

Research Institute, 1975; Matheson, 1972). In biological and
 

chemical laboratories, dioxane is employed as a solvent for
 

tissue processing, liquid scintillation counting, and
 

photochemical reactions. Nearly 18 million pounds were produced
 

for these uses in 1973 (U. S. International Trade Commission,
 

1976).
 

The carcinogenicity of dioxane has been studied extensively.
 

(Argus et al., 1965; Hoch-Ligeti et al., 1970; Argus et al.,
 

1973; Kociba et al., 1974). Dioxane was selected for testing
 

along with a series of chlorinated dibenzo-p-dioxins, some of
 

which are highly toxic contaminants of certain herbicides and
 

pentachlorophenol microbicides.
 

1 

II. MATERIALS AND METHODS
 

A. Chemical
 

The chemical tested was reagent-grade dioxane supplied toy J» T.
 

Baker Chemical Co., Phillipsburg, New Jersey. Lots No. 45468 and
 

43475 were used during the chronic studies and were analyzed to
 

confirm their identity and purity. The analysis of Lot Ho. 43475
 

was performed several months after completion of the bioa»say.
 

Vapor phase chromatography showed Lot No. 45468 to be at least
 

99.9% dioxane. Spectra were consistent with the structure of.
 

dioxane. Both lots were also analyzed by polarography for the
 

presence of sodium diethyldithiocarbamate, an inhibitor of
 

peroxide formation, stated by the manufacturer to be present at a
 

level of 0.001%. Lot No. 43475 could not be analyzed for the
 

inhibitor because of an interfering substance. In Lot So» 4544$,
 

less than 0.0002% sodium diethyldithiocarbamate was detected.
 

The presence of peroxide was measured by titratioti with titaniuffi
 

tetrachloride or sodium iodide. Lot No. 45468 had very low
 

levels of peroxide, less than 0.001% peroxide, while Let N-o.
 

43475, in contrast, had a level of 0.109% peroxide (calculated as
 

dioxane hydroperoxide). Argus et al. (1973) analyzed their 10%
 

dioxane stock solutions and tap water dilutions used in a do»ed
 

water study for peroxides, but could detect none (< 0.0002%).
 

3
 
B. Dosage Preparation
 

The dioxane solutions for this study were prepared in tap water
 

twice per week and stored in polyethylene containers. These were
 

then used to supply the water bottles for the dosed animals.
 

C. Animals
 

Osborne-Mendel rats and B6C3F1 mice of both sexes were used in
 

the chronic studies. All animals were obtained from Charles
 

River Breeding Laboratories, Inc., Wilmington, Massachusetts,
 

under a contract with the Division of Cancer Treatment, NCI.
 

Rats and mice were received at the test laboratory at approximately 4 weeks of age. They were quarantined for 1 week.
 

Animals having no visible signs of disease were then earmarked
 

and assigned to control or dosed groups according to a series of
 

random numbers.
 

D. Animal Maintenance
 

Animals were housed in temperature- and humidity-controlled
 

rooms. The temperature was maintained at 22-23°C and the
 

relative humidity at 40-50%. Fluorescent lighting was provided
 

for 12 hours each day. Room air was changed 22 times per hour
 

and exchanged through fiberglass filters.
 

Rats were housed 4 per cage and mice 10 per cage in suspended
 

4
 
polypropylene cages (Maryland Plastics, Federalsburg, Maryland),
 

covered with a wire mesh screen and a polyester filter. A woodchip bedding (Absorb-Dri®, Lab Products, Garfield, N. J. ) was
 

used in the cages. Dosed water or tap water in glass water
 

bottles with sipper tubes was available to respective groups of
 

animals ad libitum; bottles were refilled twice per week.
 

Animals were fed Wayne® Lab Blox animal meal (Allied Mills, Inc.,
 

Chicago, Illinois). Diets were available ad libitum and were
 

supplied once per week.
 

Cages, cage lids, and water bottles were sanitized at 82°C once
 

per week. Bedding was replaced once per week. Rats and mice
 

were housed in separate rooms. Untreated controls were housed in
 

the same room with the dosed animals. Rats and mice dosed with
 

dioxane were housed in the same room with rats and mice fed
 

dibenzodioxin (CAS 262-12-4), 2,7-dichlorodibenzodioxin (CAS
 

33857-26-0), and 1,2,3,4,6,7,8,9-octachlorodibenzodioxin (CAS
 

3268-87-9).
 

E. Designs of Chronic Studies
 

In this study, dioxane was administered to rats and mice at
 

concentrations of either 0.5% or 1.0% in drinking water. These
 

concentrations were chosen on the basis of doses administered in
 

previous studies (Argus et al., 1965). During the second year of
 

the study, fluid intake was measured for 1 week out of every
 

5 
month. This permitted an estimation of the average daily dioxane
 

intake, shown in tables 1 and 2. Decreased fluid consumption was
 

observed in the high-dose male mice, in which the average daily
 

intake of the test chemical was only slightly higher than that of
 

the low-dose group and did not reflect the twofold difference in
 

concentration between the low and high doses.
 

F. Clinical and Pathologic Examinations
 

Animals were observed twice daily. Body weights were measured
 

every 2 weeks for the first 12 weeks and every month during the
 

rest of the study. Measurement of food and water consumption was
 

begun during the second year of the study, and was done once per
 

month using 20% of the animals of each group as a representative
 

sample of the population.
 

Animals that were moribund were killed. All animals were necropsied whether they died or were killed, except for those lost
 

through cannibalization or autolysis. The following tissues were
 

taken at necropsy: mammary gland, trachea, lungs and bronchi,
 

heart, bone marrow, liver, gall bladder (mice) and bile duct,
 

spleen, pancreas, kidney, esophagus, thyroid, adrenal, gonads,
 

brain, stomach, nasal septum, skin, and tissue masses. At 105
 

weeks from the earliest starting date, a new necropsy protocol
 

was instituted. This affected the male controls and high-dose
 

6 
7

 

Table 1. Design of Chronic Studies of 1,4-Dioxane in Rats
 

Sex and Initial 1, 4-Dioxane Average Time on Study 

Test No. of in Drinking Dose Dosed Observed 

Group Animals3 Water (%,v/v) (ma/kg /day)b (weeks ) (weeks ) 

Male 

Matched-Control0 35 0 0 110 0 

Low -Dose 35 0.5 240(130-380) 110 0 

High-Dose0 35 1.0 530(290-780) 110 0 

Female 

Ma tched-Controld 35 0 0 110 6-7 

Low-Dose 35 0.5 350(200-580) 110 0-1
 

High-Dose 35 1.0 640(500-940) 110 0-1
 

a

All animals were 5 weeks of age when placed on study.
 

b

The mean consumption of dioxane solution per week was determined at intervals during
 

the second year of the bioassay. The average doses were calculated with the use of the
 

following formula:
 

me/kg/day = mean ml solution consumed/wk x % dioxane x density of dioxane x 10
 

mean kg body weight x 7
 

c

These groups were placed on study 1 year after the study began, to replace two original
 

groups of male rats that died during an air-conditioning failure.
 

"Untreated female controls were placed on study 5 weeks later than the dosed groups.
 
 of Chronic Studies of 1,4-Dioxane in Mice 

8

 

Sex and
 

Test


Group
 

Male
 

Ma tched-Control
 

Low -Dose
 

High-Dose
 

Female
 

Matched-Control
 

Low-Dose
 

High-Dose
 

Table 2. Design

Initial
 

 No. of
 

Animals3
 

50
 

50
 

50
 

50
 

50
 

50
 

1,4-Dioxane
 

in Drinking
 

Water (%,v/v)
 

0
 

0.5
 

1.0
 

0
 

0.5
 

1.0
 

Average
 

Dose
 

(rag /kg /day )b
 

0
 

720(530-990)
 

830(680-1150)
 

0
 

380(180-620)
 

860(450-1560)
 

a

Mice were 5 weeks of age when placed on study.
 

b

The mean consumption of dioxane solution per week was determined at
 

the second year of the bioassay. The average doses were calculated
 

following formula:
 

Time on Study0
 

Dosed Observed
 

(weeks ) (weeks )
 

90 2-3
 

90 1-2
 

90 1
 

90 1-2
 

90 1-2
 

90 0-1
 

intervals during
 

with the use of the
 

mg/kg/day = mean ml solution consumed/wk x % dioxane x density of dioxane x 10
 

mean kg body weight x 7 

c

Groups were placed on study not more than 7 weeks apart. 
groups of rats which were started a year later than the original
 

groups of rats and mice. The tissues taken after that time
 

included skin, mandibular lymph node, salivary gland, mammary
 

gland, bone marrow, thymus, larynx, trachea, lungs and bronchi,
 

heart, thyroid, parathyroid, esophagus, stomach, duodenum, colon,
 

mesenteric lymph node, liver, pancreas, spleen, kidney, urinary
 

bladder, adrenal, gonads, nasal cavity, brain, pituitary, spinal
 

cord, skeletal muscle, sciatic nerve, and tissue masses. Tissues
 

were preserved in 10% buffered formalin, embedded in paraffin,
 

sectioned, and stained with hematoxylin and eosin. All tissues
 

were examined microscopically by the pathologist.
 

A few tissues from some animals were not examined, particularly
 

from those animals that died early. Also, some animals were
 

missing, cannibalized, or judged to be in such an advanced state
 

of autolysis as to preclude histopathologic evaluation. Thus,
 

the number of animals from which particular organs or tissues
 

were examined microscopically varies, and does not necessarily
 

represent the number of animals that were placed on study in each
 

group.
 

G. Data Recording and Statistical Analyses
 

Pertinent data on this experiment have been recorded in an automatic data processing system, the Carcinogenesis Bioassay Data
 

9
 
System (Linhart et al., 1974). The data elements include descriptive information on the chemicals, animals, experimental design,
 

clinical observations, survival, body weight, and individual
 

pathologic results, as recommended by the International Union
 

Against Cancer (Berenblum, 1969). Data tables were generated for
 

verification of data transcription and for statistical review.
 

These data were analyzed using the statistical techniques
 

described in this section. Those analyses of the experimental
 

results that bear on the possibility of carcinogenicity are
 

discussed in the statistical narrative sections.
 

Probabilities of survival were estimated by the product-limit
 

procedure of Kaplan and Meier (1958) and are presented in this
 

report in the form of graphs. Animals were statistically
 

censored as of the time that they died of other than natural
 

causes or were found to be missing; animals dying from natural
 

causes were not statistically censored. Statistical analyses for
 

a possible dose-related effect on survival used the method of Cox
 

(1972) for testing two groups for equality and Tarone's (1975)
 

extensions of Cox's methods for testing for a dose-related trend.
 

One-tailed P values have been reported for all tests except the
 

departure from linearity test, which is only reported when its
 

two-tailed P value is less than 0.05.
 

10
 
The incidence of neoplastic or nonneoplastic lesions has been
 

given as the ratio of the number of animals bearing such lesions
 

at a specific anatomic site (numerator) to the number of animals
 

in which that site is examined (denominator). In most instances,
 

the denominators included only those animals for which that site
 

was examined histologically. However, when macroscopic examination was required to detect lesions prior to histologic sampling
 

(e.g., skin or mammary tumors), or when lesions could have
 

appeared at multiple sites (e.g., lymphomas), the denominators
 

consist of the numbers of animals necropsied.
 

The purpose of the statistical analyses of tumor incidence is to
 

determine whether animals receiving the test chemical developed a
 

significantly higher proportion of tumors than did the control
 

animals. As a part of these analyses, the one-tailed Fisher
 

exact test (Cox, 1970) was used to compare the tumor incidence of
 

a control group with that of a group of dosed animals at each
 

dose level. When results for a number of dosed groups (k) are
 

compared simultaneously with those for a control group, a
 

correction to ensure an overall significance level of 0.05 may be
 

made. The Bonferroni inequality (Miller, 1966) requires that the
 

P value for any comparison be less than or equal to 0.05/k. In
 

cases where this correction was used, it is discussed in the
 

11
 
narrative section. It is not, however, presented in the tables,
 

where the Fisher exact P values are shown.
 

The Cochran-Armitage test for linear trend in proportions, with
 

«
 

continuity correction (Armitage, 1971), was also used. Under the
 

assumption of a linear trend, this test determines if the slope
 

of the dose-response curve is different from zero at the onetailed 0.05 level of significance. Unless otherwise noted, the
 

direction of the significant trend is a positive dose relationship. This method also provides a two-tailed test of departure
 

from linear trend.
 

A time-adjusted analysis was applied when numerous early deaths
 

resulted from causes that were not associated with the formation
 

of tumors. In this analysis, deaths that occurred before the
 

first tumor was observed were excluded by basing the statistical
 

tests on animals that survived at least 52 weeks, unless a tumor
 

was found at the anatomic site of interest before week 52. When
 

such an early tumor was found, comparisons were based exclusively
 

on animals that survived at least as long as the animal in which
 

the first tumor was found. Once this reduced set of data was
 

obtained, the standard procedures for analyses of the incidence
 

of tumors (Fisher exact tests, Cochran-Armitage tests, etc.) were
 

followed.
 

12
 
When appropriate, life-table methods were used to analyze the
 

incidence of tumors. Curves of the proportions surviving without
 

an observed tumor were computed as in Saffiotti et al. (1972).
 

The week during which an animal died naturally or was sacrificed
 

was entered as the time point of tumor observation. Cox's
 

methods of comparing these curves were used for two groups;
 

Tarone's extension to testing for linear trend was used for three
 

groups. The statistical tests for the incidence of tumors which
 

used life-table methods were one-tailed and, unless otherwise
 

noted, in the direction of a positive dose relationship. Significant departures from linearity (P < 0.05, two-tailed test) were
 

also noted.
 

The approximate 95 percent confidence interval for the relative
 

risk of each dosed group compared with its control was calculated
 

from the exact interval on the odds ratio (Gart, 1971). The
 

relative risk is defined as Pt/pc where pt is the true binomial
 

probability of the incidence of a specific type of tumor in a
 

dosed group of animals and pc is the true probability of the
 

spontaneous incidence of the same type of tumor in a control
 

group. The hypothesis of equality between the true proportion of
 

a specific tumor in a dosed group and the proportion in a control
 

group corresponds to a relative risk of unity. Values in excess
 

13 
of unity represent the condition of a larger proportion in the
 

dosed group than in the control.
 

The lower and upper limits of the confidence interval of the
 

relative risk have been included in the tables of statistical
 

analyses. The interpretation of the limits is that in approximately 95% of a large number of identical experiments, the true
 

ratio of the risk in a dosed group of animals to that in a
 

control group would be within the interval calculated from the
 

experiment. When the lower limit of the confidence interval is
 

greater than one, it can be inferred that a statistically significant result (P < 0.025 one-tailed test when the control incidence
 

is not zero, P < 0.050 when the control incidence, is zero) has
 

occurred. When the lower limit is less than unity, but the upper
 

limit is greater than unity, the lower limit indicates the
 

absence of a significant result while the upper limit indicates
 

that there is a theoretical possibility of the induction of
 

tumors by the test chemical, which could not be detected under
 

the conditions of this test.
 

14
 
III. RESULTS - RATS
 

A. Body Weights and Clinical Signs (Rats)
 

Mean body weights of the low-dose males were higher than those of
 

the matched controls, particularly during the second year of the
 

bioassay, while those of the low-dose females were comparable
 

throughout the test period (figure 1). The weights of the highdose animals of both sexes were lower than those of the controls,
 

particularly during the second year of the bioassay. Fluctuation
 

in the growth curve may be due to mortality; as the size of a
 

group diminishes, the mean body weight may be subject to
 

variation. No clinical signs other than those of altered body
 

weights were reported.
 

B. Survival (Rats)
 

The Kaplan and Meier curves estimating the probabilities of
 

survival for male and female rats administered dioxane in the
 

drinking water at the doses of this bioassay, together with those
 

of the matched controls, are shown in figure 2.
 

In each sex, the Tarone test result for positive dose-related
 

trend in mortality is significant (P < 0.001). Departures from
 

linear trend are observed (P = 0.010 in males, P = 0.030 in
 

females), due to the relatively steep decrease in survival
 

15 
TIME ON STUDY (WEEKS) 

Figure 1. Growth Curves For Rats Administered 1,4-Dioxane in the Drinking Water 

16 
TIME ON STUDY (WEEKS) 

Figure 2. Survival Curves for Rats Administered 1,4-Dioxane in the Drinking Water 

17 
observed in the dosed groups. In male rats, 33/35 (94%) of the
 

high-dose group, 26/35 (74%) of the low-dose group, and 33/35
 

(94%) of the matched controls lived at least as long as 52 weeks
 

on study. In female rats, 29/35 (83%) of the high-dose group,
 

30/35 (86%) of the low-dose group, and all 35 of the matched
 

controls lived beyond week 52. Sufficient numbers of rats of
 

each sex were at risk for development of tumors appearing within
 

this period.
 

C. Pathology (Rats)
 

Histopathologic findings on neoplasms in rats are summarized in
 

Appendix A, tables Al and A2; findings on nonneoplastic lesions
 

are summarized in Appendix C, tables Cl and C2.
 

Neoplasms associated with administration of dioxane occurred in
 

the nasal cavity (squamous-cell carcinomas, adenocarcinomas, and
 

rhabdomyomas) in each sex, liver (hepatocellular adenomas) in
 

females, and testis/epididymis (mesotheliomas) in males.
 

The incidence of tumors of the nasal cavity was related to the
 

dioxane to which the rats were exposed. Squamous-cell carcinomas
 

occurred in 12/33 (36%) low-dose males, 16/34 (47%) high-dose
 

males, 10/35 (29%) low-dose females, and 8/35 (23%) high-dose
 

females. The first tumors were observed at week 52 in males and
 

18
 
at week 66 in females. None were found in the 33 male controls
 

and 34 female controls.
 

Nasal squamous-cell carcinomas varied morphologically from
 

minimal foci of locally invasive squamous-cell proliferation to
 

advanced growth consisting of extensive columns of epithelial
 

cells projecting either into free spaces of the nasal cavity
 

and/or infiltrating the submucosa. Although reasonably well
 

differentiated (formation of cell nests and cornification), local
 

invasiveness was common and extended to the retrobulbar tissues
 

of the eye in 1/16 high-dose males, and to the brain in 1/12 lowdose males. Distant metastasis to the lung occurred in 1/8 highdose females. Adenocarcinomas (nonkeratinizing) arose from nasal
 

mucosal epithelium in 3/34 (9%) high-dose males, 1/35 (3%)
 

low-dose, and 1/35 (3%) high-dose females. They extended
 

primarily into the free space of the nasal cavity. The neoplasms
 

were reasonably well differentiated, with varying infiltrations
 

into the submucosal tissue. Metastasis to the lung occurred in
 

1/3 high-dose males having these tumors. The single instance of
 

a benign skeletal muscle tumor (rhabdomyoma) was observed in 1/33
 

(3%) low-dose males.
 

Although hepatocellular hyperplasia (cytomegaly) occurred in both
 

dosed and control groups, hepatocellular adenomas were primarily
 

seen in livers of female rats (0/31 [0%] controls, 10/33 [30%]
 

19
 
low-dose, 11/32 [34%] high-dose). These neoplastic foci
 

consisted of proliferating hepatic cells oriented as concentric
 

cords. The foci were sharply delineated from immediate normal
 

parenchyma which yielded to compression. Hepatic cell size was
 

variable; mitoses and necrosis were rare.
 

Mesotheliomas involving the vaginal tunics of the testis/
 

epididymis were apparent in dosed animals more frequently than in
 

the control group (2/33 [6%] high-dose controls, 4/33 [12%]
 

low-dose, and 5/34 [15%] high-dose). Microscopically, these
 

growths were characterized as rounded and papillary projections
 

of mesothelial cells, each supported by a core of fibrous tissue.
 

Although other benign and malignant neoplasms occurred in various
 

tissues, each type has been encountered previously as a spontaneous lesion in the rat. Moreover, the incidences of neoplasms
 

are not related to administration of the test chemical by type,
 

site, test group, or sex.
 

Nonneoplastic responses associated with exposure to dioxane were
 

observed in the kidney (tubular degeneration), liver
 

(cytomegaly), and stomach (ulceration). Renal changes were
 

characterized within the proximal cortical tubular epithelium by
 

marked vacuolar degeneration and/or focal tubular epithelial
 

regeneration. Hyaline casts were seen on occasion. Gastric
 

20
 
ulceration of the stomach was observed in 5/28 (18%) low-dose,
 

5/30 (17%) high-dose, and no control males. Females were
 

affected negligibly.
 

Dosed rats had higher incidences of pneumonia than the controls
 

(8/30 [27%] controls, 15/31 [48%] low-dose, and 14/33 [42%] highdose males; 6/30 [20%] control, 5/34 [15%] low-dose, and 25/32
 

[78%] high-dose females), and the development of nasal carcinomas
 

may have been a contributing factor.
 

A variety of other nonneoplastic lesions were represented among
 

both control and dosed animals. Such lesions have been
 

encountered previously and are considered spontaneous events not
 

unlike those commonly observed in aging rats.
 

Based on the histopathologic examination, dioxane was
 

carcinogenic, producing squamous-cell carcinomas of the nasal
 

cavity in male and female Osborne-Mendel rats exposed to the
 

chemical in drinking water.
 

D. Statistical Analyses of Results (Rats)
 

Tables El and E2 in Appendix E contain the statistical analyses
 

of the incidences of those primary tumors that occurred in at
 

least two animals in one group and with an incidence of at least
 

5% in one or more than one group. The statistical analyses in
 

21
 
the male rats consist only of Fisher exact tests, comparing
 

incidences in the high-dose with those in the control groups.
 

These groups were tested concurrently; the low-dose group,
 

however, was started a year earlier without appropriate controls.
 

Although the incidences of tumors in the low-dose group of male
 

rats were not used for statistical analysis, they are shown in
 

table El.
 

Squamous-cell carcinomas of the nasal turbinate occurred in a
 

significantly (P < 0.001) higher proportion in the high-dose
 

group of male rats than in the control group. While no tests
 

were made using the proportion of 12/33 (36%) seen in the lowdose group, this proportion approaches the 16/34 (47%) seen in
 

the high-dose group. In females, the Cochran-Armitage test is
 

significant (P = 0.008). An indicated departure from linear
 

trend is observed (P = 0.039), because the proportion in the
 

low-dose group is slightly greater than that in the high-dose
 

group. The Fisher exact test shows that the incidences in both
 

the dosed groups are significantly higher (P _< 0.003) than that
 

in the matched controls. The statistical conclusion is that this
 

tumor in both sexes of rats is associated with the administration
 

of the test chemical.
 

In female rats, the Cochran-Armitage test result for the
 

incidence of hepatocellular adenomas is significant (P = 0.001),
 

22
 
and the Fisher exact test shows that the incidences in both the
 

low- and high-dose groups are significantly higher (P _<_ 0.001)
 

than that in the matched controls. The statistical conclusion is
 

that the incidence of this tumor in the female rats is associated
 

with administration of the test chemical. The statistical test
 

results on the incidences of this tumor in male rats are not
 

significant.
 

Significant results in the negative direction are observed in the
 

incidence of C-cell adenomas in female rats.
 

The statistical conclusion is that the incidence of squamous-cell
 

carcinomas of the nasal turbinate in both sexes of rats and the
 

incidence of hepatocellular adenomas in female rats are
 

associated with the administration of dioxane.
 

23
 

IV. RESULTS - MICE
 

A. Body Weights and Clinical Signs (Mice)
 

Mean body weights of male mice at the low-dose were comparable to
 

those of the matched controls, while at the high-dose, the mean
 

body weights were slightly elevated (figure 3). Mean body
 

weights of low-dose female mice were higher than those of the
 

controls, and body weights of the high-dose animals were lower.
 

Fluctuation in the growth curve may be due to mortality; as the
 

size of a group diminishes, the mean body weight may be subject
 

to variation. No clinical signs other than those of altered body
 

weights were reported.
 

B. Survival (Mice)
 

The Kaplan and Meier curves estimating the probabilities of
 

survival for male and female mice administered dioxane in the
 

drinking water at the doses of this bioassay, together with those
 

of the matched controls, are shown in figure 4.
 

In male mice, the Tarone test result for positive dose-related
 

trend in mortality is not significant, with at least 90% of the
 

animals in each group (45/50 [90%] in the high-dose group, 46/50
 

[92%] in the low-dose group, and 48/50 [96%] in the control
 

group) still alive at week 91. In females, the Tarone test
 

25
 
TIME ON STUDY (WEEKS) 

Figure 3. Growth Curves For Mice Administered 1,4-Dioxane in the Drinking Water 

26 
TIME ON STUDY (WEEKS) 

Figure 4. Survival Curves for Mice Administered 1,4-Dioxane in the Drinking Water 

27 
result is significant (P < 0.001), with 28/50 (56%) of the
 

high-dose group, 39/50 (78%) of the low-dose group, and 45/50
 

(90%) of the matched controls still alive at week 91. Sufficient
 

numbers of mice of each sex were at risk for development of lateappearing tumors.
 

C. Pathology (Mice)
 

Histopathologic findings on neoplasms in mice are summarized in
 

Appendix B, tables Bl and B2; findings on nonneopiastic lesions
 

are summarized in Appendix D, tables Dl and D2.
 

The incidences of neoplasms observed in the liver are tabulated
 

below:
 

MICE 

Male Female 

Untreated Low High Untreated Low High 

Control Dose Dose Control Dose Dose 

No. of tissues
 

examined
 

microscopically (49) (50) (47) (50) (48) (37)
 

Liver
 

Hepatocellular
 

carcinoma 2(4%) 18(36%) 24(51%) 0 12(25%) 29(78%)
 

Hepatocellular
 

adenoma or
 

carcinoma 8(16%) 19(38%) 28(60%) 0 21(44%) 35(95%)
 

The neoplastic hepatic parenchymal cells were irregular in size
 

and arrangement. Cells were often hypertrophic with hyper28
 
chromatic nuclei. Despite extensive proliferation, the interlacing cords of hepatic cells seldom revealed mitoses. Although
 

locally invasive within the liver, metastasis to the lung was
 

rarely observed (1/50 [2%] low-dose males).
 

The few nasal adenocarcinomas (1/48 [2%] low-dose females and
 

1/49 [2%] high-dose males) that were observed arose from
 

proliferating respiratory epithelium lining the nasal turbinates.
 

The neoplasms extended into the nasal cavity, and local tissue
 

infiltration was not extensive. Nasal mucosal polyps were rare
 

(1/48 [2%] low-dose females and 1/49 [2%] high-dose males). The
 

polyps were derived from mucus-secreting epithelium and were not
 

otherwise remarkable.
 

A variety of other benign and malignant neoplasms occurred;
 

however, each type has been encountered previously as a spontaneous lesion in the B6C3F1 mouse. It is apparent that the
 

incidences of these neoplasms are unrelated by type, site, group,
 

or sex of animal, and hence, are unattributable to exposure to
 

the chemical.
 

Of the nonneoplastic lesions represented among both control and
 

dosed animals, the increased incidence of pneumonia
 

(inflammation) and rhinitis (acute inflammation, acute
 

suppurative inflammation) was significant. Pneumonia occurred in
 

29
 
1/49 (2%) control, 9/50 (18%) low-dose, and 17/47 (36%) high-dose
 

males; 2/50 (4%) control, 33/47 (70%) low-dose, and 32/36 (89%)
 

high-dose females. Rhinitis was observed in 1/50 (2%) low-dose,
 

1/49 (2%) high-dose males; and in 7/48 (14%) low-dose and 8/39
 

(21%) high-dose females. Hepatic cytomegaly was .commonly
 

observed in dosed mice. A variety of other nonneoplastic lesions
 

were observed; such lesions have been encountered previously,
 

however, and are considered to be similar to those commonly
 

observed in aging mice.
 

Based on the histopathologic examination, dioxane was
 

carcinogenic, producing hepatocellular neoplasms in male and
 

female B6C3F1 mice exposed to the chemical in drinking water.
 

D

* Statistical Analyses of Results (Mice)
 

Tables F3 and F4 in Appendix F contain the statistical analyses
 

of the incidences of those primary tumors that occurred in at
 

least two animals in one group and with an incidence of at least
 

5% in one or more than one group.
 

In each sex, the result of the Cochran-Armitage test for positive
 

dose-related trend in proportions for the incidence of the
 

animals with either hepatocellular adenomas or carcinomas is
 

significant (P < 0.001) and the Fisher exact test shows that the
 

incidences in any of the dosed groups are significantly higher
 

30
 
(P £ 0.014) than those in the matched controls. The statistical
 

conclusion is that the incidence of this tumor in male and female
 

mice is associated with administration of the test chemical.
 

In male mice, the result of the Cochran-Armitage test on the
 

incidence of lymphomas is not significant, and the Fisher exact
 

test comparing the incidence in the low-dose group with that in
 

the matched controls indicates a probability level of 0.030,
 

which is above the 0.025 level required by the Bonferroni
 

inequality criterion when a multiple comparison is considered.
 

In females, the statistical test results have probability levels
 

greater than 0.05.
 

The result of the Cochran-Armitage test on the combined
 

incidences of hemangiomas and hemangiosarcomas in male mice is
 

significant (P = 0.047). The Fisher exact test shows that the
 

incidence in the low-dose group is significantly higher (P =
 

0.014) than that in the matched controls. Neither the Fisher
 

exact test results using the high-dose males nor the results
 

using the female groups are significant.
 

A significant trend in the negative direction is observed in the
 

incidence of animals with alveolar/bronchiolar adenomas or
 

carcinomas of the lung in male mice, where the incidence in the
 

matched controls exceeds the incidences in the dosed groups. The
 

31
 
probable reason for this negative trend is that the dosed animals
 

did not live as long as the control animals, thus isuppressing the
 

possibility of the development of tumors in the dosed groups.
 

The statistical conclusion is that the incidence of hepatocellular carcinomas in both sexes of mice is associated with the
 

administration of dioxane.
 

32 
V. DISCUSSION
 

In this bioassay, the total doses received by the "low-" and
 

"high-dose" groups in both rats and mice do not reflect the
 

twofold difference in concentration of chemical in the drinking
 

water, because of variations in the intake of the dosed water —
 

presumably due in part to decreased palatability. In addition,
 

there were wide fluctuations in intake at different time periods
 

within the groups. The mean body weights of the rats and mice
 

were not consistently affected by the administration of dioxane.
 

Rates of survival of the dosed groups of male and female rats
 

were lower than those of the corresponding controls, but
 

sufficient numbers of rats were at risk beyond week 52 on study
 

for development of tumors appearing within this period. There
 

was a positive dose-related trend in mortality in the female but
 

not in the male mice. Although only 56% of the high-dose female
 

mice survived until the end of the bioassay, sufficient numbers
 

of both male and female mice were at risk for development of
 

late-appearing tumors.
 

In rats, the incidence of squamous-cell carcinomas of the nasal
 

turbinates was statistically significant in tests both for doserelated trend in females (P = 0.008) and for direct comparison of
 

high-dose with control males (P < 0.001) and direct comparison of
 

dosed with control females (P £ 0.003) (males: controls 0/33,
 

33
 
low-dose 12/33, high-dose 16/34; females: controls 0/34, low-dose
 

10/35, high-dose 8/35). These carcinomas commonly invaded local
 

tissues and extended to the retrobulbar tissues of the eye in one
 

male and to the brain in another male. In addition,
 

adenocarcinomas (nonkeratinizing) arose from the nasal mucosal
 

epithelium in three high-dose males and in one low-dose and one
 

high-dose female. In the female, but not in the male rats, the
 

incidence of hepatocellular adenomas also was significant (P _£
 

0.001) in tests for dose-related trend and for direct comparison
 

of both low- and high-dose groups with controls (controls 0/31,
 

low-dose 10/33, high-dose 11/32).
 

In both male and female mice, the incidence of hepatocellular
 

carcinomas was statistically significant (P £ 0.001) in tests for
 

both dose-related trend and direct comparison of both low- and
 

high-dose groups with controls (males: controls 2/49, low-dose
 

18/50, high-dose 24/47; female: controls 0/50, low-dose 12/48,
 

high-dose 29/37). The incidences remained significant when
 

hepatocellular adenomas were combined with hepatocellular
 

carcinomas. Hemangiomas or hemangiosarcomas occurred in six
 

low-dose and three high-dose male mice but in no controls. The
 

incidence in the low-dose group was significantly higher than in
 

controls. Since neither the dose-related trend nor the incidence
 

34
 
in the high-dose group is significant, the tumors are not
 

considered to be related to administration of the chemical.
 

Several investigators have reported induction of carcinomas in
 

animals by dioxane. Argus et al. (1965) reported that dioxane
 

given to male Wistar rats in drinking water at a concentration of
 

1% was a hepatocarcinogen; 7/26 rats developed liver tumors at
 

days 448-455. Hoch-Ligeti et al. (1970) and Argus et al. (1973)
 

reported that administration of the compound to 120 male rats
 

(Charles River random bred, Sprague-Dawley descendant,, 1950) at
 

concentrations of 0.75% to 1.8% in the drinking water for 13
 

months led to the development of both hepatocellular carcinomas
 

and carcinomas of the nasal cavity. Kociba et al. (1974)
 

maintained Sherman strain male and female rats on drinking water
 

containing 0, 1.0, 0.1, or 0.01% dioxane for up to 716 days;
 

hepatocellular carcinomas developed in 10/66 rats at the 1%
 

level, 1/100 rats at the 0.1% level, 0/110 rats at the 0.01%
 

level, and 1/106 control rats. Nasal carcinomas occurred in 3/66
 

rats at the 1% level and in none at any other level. The high
 

dose used in the present bioassay would be comparable to the 1%
 

level used in Kociba's experiment, and nasal carcinomas and
 

hepatocellular carcinomas were found in both tests. A relatively
 

high concentration of peroxide (0.109%) was found several months
 

after completion of the bioassay in one of the lots of dioxane
 

35
 
used for the present study. It is not known whether .peroxide was
 

present in the dioxane during the study. However, dioxane
 

containing no detectable peroxide has produced similar lesions to
 

those seen in this study in rats (Argus et al., 1973), so it is
 

unlikely that the lesions in the current study were due to
 

peroxide. Torkelson et al. (1974) conducted a 2-year inhalation
 

study in rats with dioxane, using 111 ppm 5 days per week for 7
 

hours per day. Under these conditions, no lesions related to
 

administration of the dioxane were observed. Thus, carcinomas of
 

the nasal cavity of rats were observed in both the present study
 

and in previously reported studies. The hepatocellular
 

carcinomas previously reported in rats were not found in the
 

present study in rats, but they did occur in both sexes of mice,
 

and hepatocellular adenomas were found in the female rats.
 

It is concluded that under the conditions of this bioassay,
 

1,4-dioxane induced hepatocellular adenomas in female Osborne-


Mendel rats. 1,4-Dioxane was carcinogenic in both sexes of rats,
 

producing squamous-cell carcinomas of the nasal turbinates, and
 

to both sexes of B6C3F1 mice, producing hepatocellular
 

carcinomas.
 

36
 
VI. BIBLIOGRAPHY
 

Argus, M. F., Sohal, R. S., Bryant, G. M., Hoch-Ligeti, C., and
 

Arcos, J. C., Dose-response and ultrastructural alterations 

in dioxane carcinogenesis. Europ. J. Cancer 9:237-243, 

1973. 

Argus, M. F., Arcos, J. C., and Hoch-Ligeti, C., Studies on the
 

carcinogenic activity of protein-denaturing agents:
 

heptocarcinogenicity of dioxane. J. Natl. Cancer Inst.
 

15:949-958, 1965.
 

Armitage, P., Statistical Methods jln Medical Research, John Wiley
 

& Sons, Inc., New York, 1971, pp. 362-365.
 

Berenblum, I. , ed. , Carcinogenicity Testing: A Report on the
 

Panel of Carcinogenicity of the Cancer Reserach Commission
 

of UICC, Vol. 2^, International Union Against Cancer, Geneva,
 

1969.
 

Cox, D. R., Regression models and life tables. J. R_. Statist.
 

Soc. B 34(2);187-220, 1972.
 

Cox, D. R., Analysis of Binary Data, Methuen & Co., Ltd., London,
 

1970, pp. 48-52.
 

Gart, J. J., The comparison of proportions: a review of
 

significance tests, confidence limits and limits and
 

adjustments for stratification. Rev. Int. Statist. Inst.
 

39(2):148-169, 1971.
 

Hoch-Ligeti, C., Argus, M. F., and Arcos, J. C., Induction of
 

carcinomas in the nasal cavity of rats by dioxane. Brit. J.
 

Cancer 24(1):164-167, 1970.
 

Kaplan, E. L. and Meier, P. , Nonparametric estimation from
 

incomplation observations. J.^ Am. Statist., Assoc.
 

53.: 457-481, 1958.
 

Kociba, R. J. , McCollister, S. B., Park, C., Torkelson, T. R. ,
 

and Gehring, P. J., 1,4-Dioxane. I. Results of a 2-year
 

ingestion study in rats. Toxicol. Appl. Pharmacol.
 

310:275-286, 1974.
 

37
 
Linhart, M. S., Cooper, J. A., Martin, R. L. , Page, N. P., and
 

Peters. J. A., Carcinogenesis bioassay data system. Comp.
 

and Biomed. Res. 7;230-248. 1974.
 

Matheson, D., Dioxane. Encyclopaedia of Occupational Health and
 

Safety. Vol. _1, McGraw-Hill Book Co. , New York, 1972, p.
 

391.
 

Miller, R. G., Jr., Simultaneous Statistical Inference,
 

McGraw-Hill Book Co., New York, 1966, pp. 6-10.
 

Saffiotti, U. , Montesano, R., Sellakumar, A. R., Cefis, F., and
 

Kaufman, D. G., Respiratory tract carcinogenes;is in hamsters
 

induced by different numbers of administrations of benzo (a)
 

pyrene and ferric oxide. Cancer Res. 32:1073-1079, 1972.
 

Stanford Research Institute. Stage I_ Chemical Dossier, August
 

1975.
 

Stecher, P. G. , ed. , Dioxane. The Merck Index; An Encyclopedia
 

of Chemicals and Drugs, Merck & Co., Inc., Rahway, N. J. ,
 

1968, p. 384.
 

Torkelson, T. R., Leong, B. K. J. , Kociba, R. J. , Richter, W. A.,
 

and Gehring, P. J., 1,4-Dioxane. II. Results of a 2-year
 

inhalation study in rats. Toxicol Appl. Pharmacol.
 

^30:287-298, 1974.
 

United States International Trade Commission. Synthetic Organic
 

Chemicals. United States Production and Sales jof_
 

Miscellaneous Chemicals, U. S. International Trade
 

Commission, Washington, D.C., January, 1976, p. 3.
 

38
 
APPENDIX A
 

SUMMARY OF THE INCIDENCE OF NEOPLASMS
 

IN RATS ADMINISTERED 1,4-DIOXANE
 

IN THE DRINKING WATER
 

39
 

TABLE A1.

 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN MALE RATS 

ADMINISTERED 1,4-DIOXANE IN THE DRINKING WATER 

MATCHED 

CONTROL LOW DOSE 

ANIMALS INITIALL Y IN STUDY 35 35 

4NIHALS NECROPSIED 33 33 

ANIMALS EXAMINE D HISTOPATHOLOGICALLY 33 32 

INTEGUMENTAR Y SYSTEM 

*SKIN (33) (33) 

S^UAMOUS CELL CARCINOMA , INVASI V 

SV.UAMOUS CELL CARCINOMA , METASTA 2 (6%) 

FIBROMA 1 (3«) 

*SUBCUT TISSUE (33) (33) 

FIBROMA 3 (9%) 1 (3X) 

FIBBOSARCCMA 

LIPOBA 1 (3*) 

RESPIRATOR Y SYSTE M 

*NASA L TURBINAT E (33) (33) SUUAMOU S CELL CARCINOM A

 12 (36%) 

ADENOCARCINOMA, NOS 

RHABDOMYCM A 1 (3*)

 

#LON G (30) (31) 

S^UAMOUS CELL CARCINOMA, METASTA 

TKANSITIONAL-CEL L CARCINOMA , MET 1 (3X) 

ADENOCARCINOMA , NOS, METASTATIC 

ALVEOLAR/BRCNCHIOLA R ADENOM A 

ALVEOLAR/BECNCHIOLAR CARCINOMA 1 (3%) 

HEMATOPOIETIC SYSTEM 

*MULIIPLE ORGAN S (33) (33) 

MALIGNAN T IYMPHOMA , NO S 

fSPLEEN 

SARCOMA , NCS 

(31) 

1 (3%) 

(32) 

HjjMANSIOM A 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

HIGH DOSE 

35 

34 

33 

(34) 

1 (3)6) 

(34) 

1 (3%) 

1 (3») 

(34) 

16 (47%) 

3 (9%) 

(33) 

1 (3%) 

1 (3X) 

1 (3«) 

(34) 

1 (3X) 

(30) 

1 I3X.1__ 

41 
TABLE A1. MALE RATS: NEOPLASMS (CONTINUED) 

MATCHED 

CONTROL LOW DOS£ 

#MANDIBULA R I. NODE (22) 

S^UAMOOS CELL CARCINOMA , METAST A 

ADENOCAECINOHA , NOS, METASTATIC 

CIRCULATOR Y SYSTEM 

NONi. 

DIGESTIVE SYSTE M 

OLIVER (31 ) (32) 

HhPATOCELLULA E ADENOM A 2 (6*) 1 (3*) 

HiPATOCELIULA R CARCINOM A 1 (3S) 

HEMANGIOSAECOM A 1 (3% ) 

URINAR Y SYSTE M 

ttKIDNEY (31) (31) 

L1POSARCOMA 1 (3% ) 1 (3%) 

HAMARTOM A 1 (3%) 

#KIDNEY/CORTE X (31) (31) 

ADENOMA , NOS 1 (3% ) 

tURINAR Y BLACEE R (28) (2) 

THANSITIONAL-CEL L CARCINOM A 1 (50X| 

ENDOCfilNE SYSTE M 

#PITUITAR Y 

ADENOMA , NO S 

(16 ) 

2 (13% ) 

(1) 

CHROMOPHOE E ADENOM A 1 (6X) 

#ADRt,NA L (30) (24) 

CORTICA L ADENOM A 

PHEOCHROMCCYTCM A 6 (20% ) 

#ADRtNA L CORTE X 

ADENOCAHCINCMA , NO S 

(30) (24 ) 

1 (4%) 

#THYfiOID 

FOLLICULAR-CELL ADENOM A 

(29)

2 172). _ (17) 

f NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

HIGH DOSE 

(15)

1 (7X) 

1 (7X) 

(33) 

1 (3%) 

(33) 

1 (3% ) 

(33) 

(27 ) 

(15) 

1 (7% ) 

(33) 

1 (3% ) 

2 (6X) 

(33) 

(31) 

42
 
TABLE A1. MALE RATS: NEOPLASMS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE 

FOLLICULAfi-CELL CARCINOMA 

C-CELL ADENOM A 

CYSTADENOMA , NOS 

1

3

 (3X) 

 (10%) 1 (6%) 

1 (6«) 

tTHYROID FOLLICLE 

CYSTADENCKA , NOS 

(29) (17) 

1 (6X) 

#PARATHYROI E 

ADENOMA , NOS 

(25) 

2 (8») 

CO 

#PANCREATIC ISLETS 

ISLET-CELL ADENOM A 

(24) 

1 (H%) 

(12) 

REPRODUCTIVE SYSTEM 

*MAMMAR Y GLAN D (33) (33) 

ADENOCARCINOMA , NOS 1 (3X) 

FIBROADENCM A 2 (6*) 

#PROSTATE (29) (2) 

ADENOCARCINOMA , NOS 

#TESTIS (32) (23) 

INTERSTITIAL-CELL TOHOR 1 (H%) 

tTUNICA ALBUGINE A (32) (23) 

MESOTHELIOMA, NOS 3 (13X) 

NERVOU S SYSTE M 

tBRAIN (31) (29) 

SQUAMOUS CELL CARCINOMA , METASTA 1 (351) 

ADENOCARCINOMA , NOS, METASTATIC 

GLIOMA, NCS 

SPECIAL SENSE ORGAN S 

*EYE (33) (33) 

ADENOCARCINOMA , NOS, BETASTATIC 

MUSCULOSKELETAL SYSTEM 

NQfifi 

* NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

HIGH DOSE 

1 (3%) 

(31) 

(2«) 

(24) 

1 (4*) 

(34) 

(3D

1 (3X) 

(31) 

(31) 

2 (6X) 

(32) 

1 (3X) 

2 (6X) 

(34) 

1 (3X) 

43
 
TABLE A1. MALE RATS: NEOPLASMS (CONTINUED) 

EODY CAVITIES
 

*TUNICA VAGINALIS
 

MESOTHELIOMA, NOS
 

ALL OTHER SYSTEMS
 

ADIPOSE TISSUE
 

LIPOMA
 

ANIMAL DISPOSITION SOBMAEY
 

ANIMALS INITIALLY IN STUDY
 

NATURAL DEATHS
 

MORIBUND SACRIFICE
 

SCHEDULED SACRIFICE
 

ACCIDENTALLY KILLED
 

TERMINAL SACRIFICE
 

ANIMAL MISSING
 

3 INCLUDES AUTCLYZED ANIMALS
 

TUMOR SUMMARY
 

TOTAL ANIMALS WITH PRIMARY 1PUMORS*


TOTAL PBIMARY TUMORS
 

TOTAL ANIMALS WITH BENIGN Tt IMORS


TOTAL BENIGN TUHORS
 

TOTAL ANIHALS WITH MALIGNAN1 P TUMORS


TOTAL MALIGNANT TUMORS
 

TOTAL ANIMALS WITH SECONDARY : TUMORS*
 

TOTAL SECONDARY TUMORS
 

TOTAL ANIHALS WITH TUMORS US ICERTAIN-
 BENIGN OR MALIGNANT
 

TOTAL UNCERTAIN TUMORS
 

TOTAL ANIMALS WITH TUMORS UJ ICERTAIN-


PRIMARY OR HETASTATIC
 

TOTAL UNCERTAIN TUMORS
 

MATCHED
 

CONTROL
 

(33)
 

2 (6%)
 

1
 

35
 

20
 

15
 

 20
 

32
 

 17
 

25
 

4
 

5
 

2
 

2
 

LOW DOSE
 

(33)
 

4 (12X)
 

1
 

35
 

31
 

2
 

2
 

18
 

36
 

8
 

12
 

15
 

17
 

3
 

4
 

4
 

7
 

HIGH DOSE
 

(34)
 

5 (15%)
 

1
 

35
 

26
 

5
 

4
 

27
 

43
 

7
 

11
 

23
 

25
 

5
 

7
 

5
 

7
 

* PBIBARY TUBOHS: ALL TUHORS EXCEPT SECONDARY TUHORS
 

* SECONDARY XUHORS: BETASTATIC TDBORS OR TUBORS INVASIVE INTO AN ADJACENT ORGAN
 

44 
TABLE A2.

 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN FEMALE RATS 

ADMINISTERED 1,4-DIOXANE IN THE DRINKING WATER 

ANIMAL S INITIALL Y IN STUD Y 

ANIMAL S NECECPSIE D 

ANIMALS EXAMINE D HISTOPATHOLOGICALLY 

INTEGUHENTAR Y SYSTEM 

*SKIN 

FIBROM A 

*SOBCUT TISSUE 

FIBROM A 

FIBROSARCCM A 

EESPIfiATOR Y SYSTEM 

*NASAL TURBINAT E 

SQUAMOU S CELL CARCINOM A 

ADENOCARCINOMA , NO S 

*LUN G 

SiJUAMOU S CEL L CARCINOMA ,

HEMATOPOIETIC SYSTE M 

fSPL£EN 

HEMANGIOM A 

#MESENTERIC I. NODE 

MALIGNAN T LYMPHOMA , NO S 

CIRCULATOR Y SYSTE M 

*MES£NTERIC AETER Y 

HiMANGIOM A 

DIGESTIVE SYSTE M 

fLIVER 

AfiENOCARCIfiCKA^NOS _

 METAST A 

_

MATCHED 

CONTROL LOW DOSE 

35 35

 

34 35

 

31 34 

(34) (35) 

1 (3X) 

(34 ) (35) 

1 (3%) 2 (6«) 

1 (3%) 

(34) (35) 

10 (29S) 

1 (3%) 

(30) (34) 

(30) (34) 

2 (6%) 

(25) (5) 

1 (20%) 

(34) (35) 

1 (3X) 

(31) (33)

 

. 

HIGH DOSE 

35 

35 

32 

(35) 

1 (3%) 

(35) 

2 (6%) 

(35) 

6 (23%) 

1 (3%) 

(32 ) 

1 (3X) 

(32) 

(5) 

(35) 

(32) 

1 J3X1 . 

# NUMBE R OF ANIMAL S WITH TISSUE EXAMINE D MICROSCOPICALLY 

* NUMBER OF ANIMAL S NECROPSIE D 

45 
TABLE A2. FEMALE RATS: NEOPLASMS (CONTINUED) 

HEPATOCELLULA R ADENOM A 

HiMANSIOSAECOM A 

*BILE DUCT 

BILE DUCT ADENOM A 

URINAR Y SYSTE M 

#KIDNE Y 

FIBROSARCOMA , METASTATIC 

FIBROADENCMA 

HAMARTCM A 

#KIDNEY/CORTE X 

ADENOMA , NO S 

ENDOCttlNE SYSTE M 

•PITUITARY 

ADENOMA , NOS 

CHROMOPHOBE ADENOM A 

# ADRENA L 

CORTICAL ADENOM A 

PHEOCHEOMOCYTOMA 

#THYROID 

C-CELL ADENOM A 

CYSTADENOHA , NOS 

#THYROID FOLLICLE 

CYSTADENCKA , NOS 

#PANCREATIC ISLETS 

ISLET-CELL ADENOM A 

REPRODUCTIVE SYSTEM 

*MAHMAR Y GLAN D 

ADENOMA, NOS 

ADENOCARCINOMA , NOS 

CYSTADENOMA , NOS 

FIBRQMA 

MATCHED 

CONTROL 

(34) 

(31) 

1 (3X) 

(31) 

(18) 

4 (22%) 

(30) 

1 (3X) 

(28) 

4 (14%) 

(28) 

2 (7%) 

(29) 

1 (3«) 

(34) 

3 (9S) 

1 (3X) 

1 J3S£ __ 

LOW DOSE 

10 (30X) 

(35) 

(34) 

1 (3S) 

(34) 

(3) 

1 (33S) 

(32) 

1 (3X) 

(20) 

(20) 

1 (5») 

(15) 

(35) 

3 (9%) 

1 (3*) 

HIGH DOSE 

11 (34S) 

1 (3X) 

(35) 

1 <3X) 

(32) 

1 (3*) 

1 (3X) 

(32) 

1 (3X) 

(2) 

(29) 

1 (3X) 

(18) 

1 (6X) 

(18) 

(16) 

(35) 

1 (3X) 

t NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

46 
TABLE A2. FEMALE RATS: NEOPLASMS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

FIBROADENCH A 13 (38«) 16 (46X) 10 (29*) 

IUTEBUS

ADENOCARCINCMA, NOS, INVASIVE

PAPILLAR Y CYSTADENOMA , NOS

PftPILLAR Y CYSTADENOCARCINOHA,NO S

FIBROMA

 (30)

 1

 1

 (38) 

 (3») 

 (3U)

 1 (3%) 

 (28) 

1 (4%) 

tOVARY

CYSTADENCHA, NOS

THECOMA

HEMANGIOMA

 (26) (23)

 1 (H%) 

 (22) 

1 (5%) 

2 (9X) 

NERVOU S SYSTER 

*FRONTAL LOBE

ADENOCARCINOMA , NOS, BSTASTATIC

 (31) (31) (28) 

1 (4%) 

SPECIAL SENSE ORGAN S 

*HARDERIA N GLAND

ADENOCARCINCHA , NOS, INVASIV E

 (3U)

 1 (3X) 

 (35) (35) 

HUSCULOSKELETAl SYSTEM 

NONE 

BODY CAVITIES 

*ABDOMINAL HAIL

FIBROSARCOHA

 (3«)

 1 (3%) 

 (35) (35) 

ALL OTHER SYSTEMS 

SITE UNKNOW N 

SaUAMQUS_CJLL_CARCINOMA J 

t NUHBER

* NUMBER

 OF

 OF

 ANIMALS

 ANIMALS

 HITH TISSUE

 NECROPSIED 

 EXAMINE D MICROSCOPICALLY 

47 
TABLE A2. FEMALE RATS: NEOPLASMS (CONTINUED) 

MATCHED
 

CONTROL LOW DOSE HIGH DOSE
 

ANIMAL DISPOSITION SUMMARY 

ANIHALS INITIALLY IN STUDY

NATURAL DEATHS

MORIBUND SACRIFICE

SCHEDULED SACRIFICE 

ACCIDENTALLY KILLED 

TERHINAL SACRIFICE

ANIMAL MISSING 

 35

 14

 21

 35 

 29 

2 

4 

35 

31 

1 

3 

3 INCLUDES AUTCLYZED ANIMALS 

TUMOR SUHNARY
 

TOTAL ANIMALS WITH PRIMARY TUMORS* 22 28 21
 

TOTAL PRIMARY TUMORS 34 5 a 47
 

TOTAL ANIMALS WITH BENIGN TUMORS 20 22 18
 

TOTAL BENIGN TUMOBS 31 42 34
 

TOTAL ANIMALS WITH MALIGNANT TUMORS 3 12 12
 

TOTAL MALIGNANT TUMORS 3 12 13
 

TOTAL ANIMALS WITH SECONDARY TUMORSt 3 2
 

TOTAL SECONDARY TUMORS 3 2
 

TOTAL ANIMALS WITH TUMORS UNCERTAIN-
 BENIGN OR MALIGNANT
 

TOTAL UNCERTAIN TUMORS
 

TOTAL ANIMALS WITH TUMORS UNCERTAIN-
 PHInARY OR HETASTATIC
 

TOTAL UNCERTAIN TUMORS
 

* PRIMARY TUMORS: ALL TUMORS EXCEPT SECONDARY TUMORS
 

# SECONDARY TUMORS: METASTATIC TUMORS OR TUMORS INVASIVE INTO AN ADJACENT ORGAN
 

48
 
APPENDIX B
 

SUMMARY OF THE INCIDENCE OF NEOPLASMS
 

IN MICE ADMINISTERED 1,4-DIOXANE
 

IN THE DRINKING WATER
 

49
 

TABLE B1.

 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN MALE MICE 

ADMINISTERED 1,4-DIOXANE IN THE DRINKING WATER 

-^ ' ' 

MATCHED 

CONTROL LOW DOSE 

ANIMALS INITIALLY IN STUDY

ANIMALS NECROPSIED

ANIMALS EXAMINED HISTOPATHOLOGICALLY

 50 

 49 

 49 

50 

50 

50 

INTEGUMENTARY SYSTEM
 

*SKIN (49) (50)
 

PAPILLOMA, NOS 1 (2%)
 

HEMANGIOSAECOMA
 

*SUBCUT TISSUE (49) (50)
 

SEBACEOUS ADENOMA 1 (2%)
 

FIBROSARCCMA 4 (8«)
 

LiilOMYOSAECOMA 1 (2%)
 

RESPIRATORY SYSTEM
 

*NASAL TURBINATE (49) (50)
 

AuENOCARCINCMA, NOS
 

#LUNG (49) (50)
 

H&PATOCELLULAR CARCINOMA, METAST 1 (2%)
 

ALVEOLAR/EBONCHIOLAR ADENOMA 8 (16%) 3 (6%)
 

ALVEOLAR/BRONCHIOLAR CARCINOMA
 

HEMATOPOIETIC SYSTEM
 

^MULTIPLE ORGANS (49) (50)
 

MALIGNANT IYMPHOMA, NOS 2 (4%)
 

tSPLEEN (48) (49)
 

HEMANGIOMA 2 (U%)
 

HEMANGIOSARCOMA 2 (4%)
 

HEMANGIOSAECCMA, METASTATIC
 

MALIGNANT LYMPHOMA, NOS 3 ((,%)
 

MAST-CELL SARCOMA, METASTATIC 1 (2X)
 

#PANCREATIC I. NODE (1) (2)
 

HEM. AN G 10 SARCOMA,. METASTATIC 1 ^50%).
 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

HIGH DOSE
 

50
 

49
 

49
 

(49)
 

1(2%)
 

(49)
 

(49)
 

1 (251)
 

(47)
 

2 (4%)
 

1 (2%)
 

(49)
 

1 (2%)
 

(43)
 

2 (5%)
 

1 (2%)
 

1 (2%)
 

(D
 

51
 
TABLE B1. MALE MICE: NEOPLASMS (CONTINUED) 

(tLIViiR 

MAST-CEL L SARCOMA , METASTATIC 

#STOMAC H 

MAST-CELL SARCOM A 

#KIDNE Y 

MAST-CEL L SARCOMA , METASTATIC 

CIRCULATORY SYSTEM 

NONr, 

DIGESTIVE SYSTE M 

fLIVER 

HEPATOCELLULA R ADENOM A 

HriPATOCELLULA R CARCINOM A 

*BILb DUCT 

BILE DUCT CARCINOM A 

fPANCREA S 

HiMANGIOM A 

**STOMACH 

S^UAMOUS CELL PAPILLOMA 

SgUABOU S CELL CARCINOM A 

UBINAri Y SYSTE M 

NONli 

ENEOCBIN E SYSTEM 

tTHYHOID 

PAPILLAR Y CYSTADENOMA , NOS 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

("9) (50) 

1 (256) 

(47) 

(49) (49) (47) 

1 (2%) 

(49) (50) (48) 

1 (2%) 

(49) 

6 (12S) 

2 (H%) 

(50) 

1 (256) 

18 (36S) 

(47) 

4 (9%) 

24 (5156) 

(49 ) (50) (49) 

1 (2)6) 

(42) (38) (31) 

2 (5%) 

(49) 

1 (2%) 

(49) (17) 

1 (2%) 

(39) (38) (38) 

1 (356) 

t NUMBEK OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

52
 
TABLE B1. MALE MICE: NEOPLASMS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

NERVOU S SYSTEM 

NONE 

SPECIAL SENSE ORGAN S 

NONE 

HUSCULOSKELETAI SYSTEM 

NONE 

BODY CAVITIES 

NONE 

ALL OTHER SYSTEMS 

NONE 

ANIMA L DISPOSITION SUMMAR Y 

ANIHALS INITIALLY IN STUDY

NATURA L DEATHS

MORIBUND SACRIFICE 

SCHEDULED SACRIFICE 

ACCIDENTALLY KILLED 

TERMINAL SACRIFICE

ANIMA L MISSING 

 50

 2 

 48

 50

4 

 46

 50 

5 

 45 

* NUHBEB OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY 

* NUHBER OF ANIMALS NECBOPSIED 

a^IUCLUDBS AUTOLYZgD AHIMALS 

53
 
TABLE B1. MALE MICE: NEOPLASMS (CONTINUED) 

TOHOB SUMMARY
 

TOTAL ANIMALS WITH PRIMARY TUMOBS*


TOTAL PRIMARY TUMORS


TOTAL ANIMALS WITH BENIGN TUMORS


TOTAL BENIGN TUMORS


TOTAL ANIMALS WITH MALIGNANT TUMORS


TOTAL MALIGNANT TUMORS


TOTAL ANIMALS WITH SECONDARY TUMORS*
 

TOTAL SECONDARY TUMORS
 

TOTAL ANIMALS WITH TUMORS UNCERTAIN-
 BENIGN OR MALIGNANT
 

TOTAL UNCERTAIN TUMORS
 

TOTAL ANIMALS WITH TUMORS UNCERTAIN-
 PRIdARY 08 METASTATIC
 

TOTAL UNCERTAIN TUMOES
 

MATCHED
 

CONTROL LOW DOSE HIGH DOSE
 

 16 28 33
 

 21 «0 38
 

 1U 7 8
 

 17 10 8
 

U 24 27
 

 1* 30 30
 

2 1
 

5 1
 

* PRIMARY TUMORS: ALL TUMORS EXCEPT SECONDARY TUMORS
 

# SECONDARY TUMORS: METASTATIC TUMOHS OR TUMORS INVASIVE INTO AN ADJACENT ORGAN
 

54 
TABLE B2.

 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN FEMALE MICE 

ADMINISTERED 1,4-DIOXANE IN THE DRINKING WATER

 

MATCHED 

CONTROL LOW DOSE 

ANIMAL S INITIAIL Y IN STUD Y 5 0 50 

ANIMAL S HISSING 1 

ANIMAL S NECROPSIE D 50 48 

ANIMAL S EXAMINE D HISTOPATHOLOGICALLY 5 0 48 

INTEGUMENTAR Y SYSTEM 

*SUBCUT TISSU E (50) (48)

 

FiBROSARCOMA 1 (2%) 2 (4%)

 

BHABDOMYOSABCOH A 1 (2%) 

RESPIRATOR Y SYSTE M 

*NASA L TURBINAT E (50) (48)

 

PAPILLARY ADENOCAHCINOMA 1 (2%)

 

#LUN G (50) (47)

 

ALVEOLAR/EEONCHIOLA R ADENOH A 3 (6%) 

ALVEOLAR/ERONCHIOLA R CARCINOM A 

FIBROSARCCKA , METASTATIC 1 <2X)

 

HhMANGIOSARCOM A 1 (2%) 

HEMATOPOIETIC SYSTEM 

*MULTIPLE ORGAN S (50) (48)

 

MALIGNAN T IYMPHOMA , NOS 4 (8X) 3 {6XJ

 

MALIG.LYMPHOMA , HISTIOCYTIC TYPE 2 (4%) 1 (2%)

 

GfiANOLOCYTIC LEUKEMIA 1 (2%)

 

#SPLEEN (50) (46)

 

HEMANGIOM A 2 (4X)

 

HEMANGIOSAECOMA, METASTATIC 1 (2%)

 

MALIGNAN T LYMPHOMA , NOS 1 (2X)

 

*LYMPH NODE (5) (D

 

HEMANGIOSARCOMA , BETASTATIC 1 (20X) 

*ADIPOSE TISSUE (50) (48) 

flAtIGfiMI_lX»£flOMit NOS 1 J2S1-. __ 

# NOMBE8 OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

HIGH DOSE 

50 

39 

39 

(39) 

(39) 

(36) 

2 (6X) 

1 (3X) 

(39) 

4 (10X) 

(37) 

4 (11X) 

(«) 

(39) 

55 
TABLE B2. FEMALE MICE: NEOPLASMS (CONTINUED) 

UUNG
 

MALIGNANT LYMPHOMA, NOS
 

#LIVER
 

MALIGNANT 1YMPHOBA. NOS
 

CIRCULATORY SYSTEM
 

NONi,
 

DIGESTIVE SYSTEM
 

#LIVER
 

HEPATOCEILULAR ADENOHA
 

HEPATOCELLULAfi CARCINOMA
 

URINAHY SYSTEM
 

NONE
 

ENCOCfilNE SYSTEM
 

tTHYBOID
 

FOLLICULAR-CELL ADENOMA
 

(PANCREATIC ISLETS
 

ISLET-CELI ADENOMA
 

REPRODUCTIVE SYSTEM
 

*VAGINA
 

HEHANGIOSARCOMA
 

#UTERUS
 

H£MANGIOSARCOMA
 

tOVABY
 

TEHATOMA, BENIGN
 

TERATOHA, NOS
 

NERVOUS SYSTEM
 

__MQHB
 

t NUMBER OF ANIMALS WITH TISSUE

* NUMBER OF ANIMALS NECROPSIED 

MATCHED
 

CONTROL LOW DOSE
 

(50)	 (47)
 

1 (2X)
 

(50)	 (48)
 

1 (2%)
 

(50) (<»8)
 

9 (19X)
 

12 (25*)
 

(39)	 (35)
 

1 (3*)
 

(26)	 (30)
 

1 (3X)
 

(50)	 (US)
 

1 (2%)
 

(49)	 (46)
 

1 (2*)
 

(20)	 (24)
 

1 (4«)
 

 EXAMINE D MICROSCOPICALLY 

56 

HIGH DOSE
 

(36)
 

(37)
 

(37)
 

6 (16X)
 

29 (78X)
 

(19)
 

(19)
 

(39)
 

(34)
 

(20)
 

1 (5X)
 
TABLE B2. FEMALE MICE: NEOPLASMS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

SPECIAL SENSE ORGAN S 

*EYE

SO.UANOUS CELL CARCINOM A

 (50) (48) (39) 

1 (3%) 

BOSCULOSKELETAI SYSTEM 

NO Hi, 

BODY CAVITIES 

*PERITONEDM

LYMPHANGICH A

 (50)

 1 (2%) 

 (48) (39) 

A LL OTHER SYSTEM S 

NONt 

ANIMA L DISPOSITION SUMMAR Y 

ANIilALS INITIALLY IN STUD Y

NATURA L DEATHS

MOHIBUN D SACRIFICE 

SCHEDULED SACRIFICE 

ACCIDENTALLY KILLED 

TERMINA L SACRIFICE

ANIMA L MISSIN G

 50

 5

 45

 50

 10

 39

 1 

 50 

 22 

 28 

2 IflCiJlDfiS JUJ1C.1Y.ZE.C iNIfiiiS _ _ 

t NUMBER OF ANIMALS WITH TISSUE EXAMINED

* NUMtiER OF ANIMALS NECROPSIED 

 MICROSCOPICALLY 

57 
TABLE B2. FEMALE MICE: NEOPLASMS (CONTINUED) 

MATCHED
 

CONTROL LOW DOSE HIGH DOSE
 

TUMOH SOHMARY
 

TOTAL ANIMALS WITH PRIMARY TUMORS*


TOTAL PRIMARY TUMORS


TOTAL ANIMALS WITH BENIGN TDMORS


TOTAL BENIGN TUMORS


TOTAL ANIMALS WITH MALIGNANT TUMORS


TOTAL MALIGNANT TUMORS


TOTAL ANIMALS WITH SECONDARY TUMORS*


TOTAL SECONDARY TUMORS


TOTAL ANIMALS WITH TUMORS UNCERTAIN-


BENIGN OR MALIGNANT


TOTAL UNCERTAIN TUMORS


TOTAL ANIMALS WITH TUMORS UNCERTAIN-


PRIMARY OR HZTASTATIC
 

TOTAL UNCERTAIN TUMORS
 

 12


 12


 4


 4


 8


 8


 1


 1


 31 35
 

 ui ua
 

 1U 6
 

 14 8
 

 21 30
 

 27 39
 

2
 

2
 

1
 

1
 

* PRIl'iARY TUMORS: ALL TUMORS EXCEPT SECONDARY TUMORS
 

# SECONDARY TUMORS: METASTATIC TUMORS OR TUMORS INVASIVE INTO AN ADJACENT ORGAN
 

58
 
APPENDIX C
 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS
 

IN RATS ADMINISTERED 1,4-DIOXANE
 

IN THE DRINKING WATER
 

59
 

TABLE C1. 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN MALE RATS 

ADMINISTERED 1,4-DIOXANE IN THE DRINKING WATER 

1HATCHED
 

(CONTROL LOW DOSE


ANIMALS INITIALLY IN STUDY 35 35
 

ANIMALS NECROESIED 33 33
 

ANIMALS EXAMINED HISTOPATHOLOGICALLY 33 32
 

INTEGUMENTARY SYSTEM
 

*SKIN (33) (33)
 

EPIDERMAL INCLUSION CYST 1 (3%)
 

*SUBCUT TISSUE (33) (33)
 

GHANULOMA, NOS 1 (3%)
 

RESPIBATORY SYSTEM 

*NASAL TURBINATE 

INFLAMMATION, HEMORRHAGIC 

INFLAMMATICN, ACUTE 

INFLAMMATION, ACUTE SUPPURATIVE 

INFLAMMATION, CHRONIC 

(33) 

5

6

2

 (15%) 

 (18%) 

 (6%) 

(33) 

2

2

16

 (6%) 

 (6%) 

(18%) 

tTRACHEA 

INFLAMMATION, ACUTE SUPPURATIVE 

INFLAMMATICN, CHRONIC 

INFLAMMATION, CHBONIC SUPPUBATIV 

ABSCESS, CHRONIC 

(30) 

1 (3%) 

7 (23%) 

2 (7%) 

(23) 

2 (9%) 

1 (4%) 

#LUNG 

CONGESTION, NOS 

EDEMA, NOS 

PNEUMONIA, ASPIRATION 

PNEUMONIA, CHBONIC MURINE 

(30) 

1 (3%) 

1 (3%) 

8 (27%) 

(31) 

5

15

 (16X) 

 (4831) 

HEMATOPOIETIC SYSTEM
 

#BONK HARROW (31) (15)
 

HEMATOPOIETIC TISSUE DISORDER 1 (3%)
 

HYPERPLASIA, HEMATOPOIETIC 3 (10%) 3 (20»)
 

#SPL£EN (31) (32)
 

IN£LAHSATIONA CHRONIC _ . 6 J1951L
 

* NUMBER OF ANIMAL S WITH TISSUE EXAMINED MICROSCOPICALLY 

* NUMBER OF ANIMALS NECROPSIED 

61 

1HIGH DOSE
 

35
 

34
 

33
 

(34)
 

1 (3%)
 

(34)
 

(34)
 

16 (47%)
 

1 (3%)
 

(33)
 

4 (12%)
 

1 (3X)
 

(33)
 

1 (3X)
 

14 (42%)
 

(32)'
 

9 (28%)
 

(30)
 

i_.QOSl_
 
TABLE C1. MALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED
 

CONTROL LOW DOSE
 

HEMOSIDEFOSIS 3 (10*) 5 (16X)
 

ATROPHY, NOS
 

LYMPHOID EEPLETION
 

H2MATOPOIESIS 3 (10%) 8 (25X)
 

ISPLilNIC FOLLICLES (31) (32)
 

Al'ROPHY, NOS 1 (3*)
 

#MANDIBULAR L. NODE (22)
 

INFLAMMATION, CHRONIC
 

HYPERPLASIA, LYHPHOID 5 (23X)
 

#BHONCHIAL LYMPH NODE (22)
 

HEMORRHAGE 1 (5X)
 

#THYMUS (3)


ATROPHY, NOS 3 (100X)
 

CIRCULATORY SYSTEM
 

fHEAET (30) (32)
 

CALCIFICATION, DYSTROPHIC 2 (6X)
 

tMYOCABDIUM (30) (32)
 

INFLAMMATION, NOS
 

INFLAMMATION, CHRONIC U (13X) 2 (6X)
 

DEGENERATION, NOS 1 (3X)
 

tENDOCARDIUM (30) (32)
 

FIBROSIS
 

*AORTA (33) (33)
 

METAPLASIA, OSSEOUS
 

*PULHONARY ARTERY (33) (33)
 

CALCIFICATION, DYSTROPHIC 1 (3X)
 

DIGESTIVE SYSTEM
 

#LIVER (31) (32)
 

CYST, NOS 1 (3X)
 

DEGENERATION, NOS 3 (9X)
 

NBCROSIS, FOCAL 1 (3X)
 

HITAMQRBHCSIS FATTY ._ _ 2 J6X1 fi J12S1
.
 

I NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 * NUMBER OF ANIMALS NECBOPSIED
 

HIGH DOSE
 

11 (37S)
 

8 (21%)
 

1 (3X)
 

H (13X)
 

(30)
 

(15)
 

1 (7X)
 

1 (7X)
 

(15)
 

(2)
 

2 (100X)
 

(33)
 

1 (3X)
 

(33)
 

1 (3X)
 

1 (3X)
 

(33)
 

1 (3X)
 

(34)
 

1 (3X)
 

(34)
 

(33)
 

7_J2JJI_
 

62
 
TABLE C1. MALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

ATROPHY, NOS
 

HYPERPLASIA, NOS
 

ANGIECTASIS
 

#LIVER/CENTRILOBULAH
 

NECROSIS, NOS
 

*BILh DUCT
 

INFLAMBATICN, CHRONIC
 

HYPERPLASIA, NOS
 

#PANCREAS
 

PERIARTERITIS
 

#STOHACH
 

ULCER, NOS
 

ULCER, ACUTE
 

ULCER, CHRCNIC
 

URINA&Y SYSTEM
 

tKIDNEY
 

MINERALIZATION
 

INFLAMMATION, ACUTE SUPPURATIVE
 

ABSCESS, NOS
 

INFLAMMATION, CHRONIC
 

PYELONEPHRITIS, CHRONIC
 

CALCIFICATION, DYSTROPHIC
 

fKIDNEY/CORTEX
 

CALCIFICATION, DYSTROPHIC
 

#PERIRENAL TISSUE
 

HEMORRHAGE
 

#KIDNEY/TUBULE
 

CAST, NOS
 

DEGENERATION, NOS
 

ATROPHY, NCS
 

RuGENERATICN, NOS
 

fUBINARY BLADDER
 EDEMA, NOS
 

INFLAMMATION, CHRONIC
 _ HYPERPLASIA^PAPILLARY,
 

MATCHED
 

CONTROL
 

5 (16X)
 

1 (3X)
 

(31)
 

(33)
 

8 (2H%)
 

<2t)
 

1 (UX)
 

(31)
 

(31)
 

23 (7«X)
 

1 (3%)
 

(31)
 

(31)
 

(31)
 

(28)
 

2 (7X)
 

LOW DOSE
 

3 (9%)
 

2 (6X)
 

(32)
 

(33)
 

1 (3X)
 

3 (9X)
 

(12)
 

(28)
 

1 (<**)
 

3 (11*)
 

1 (<»X)
 

(31)
 

1 (3%)
 

2 (6X)
 

(31)
 

(31)
 

1 (3X)
 

(31)
 

20 (65X)
 

(2)
 

HIGH DOSE
 

2 (6X)
 

11 (33X)
 

2 (6X)
 

(33)
 

1 (3X)
 

(34)
 

2 (6X)
 

<2U)
 

(30)
 

5 (17X)
 

(33)
 

5 (15X)
 

1 (3X)
 

2 (6X)
 

(33)
 

1 (3X)
 

(33)
 

(33)
 

1 (3X)
 

27 (82X)
 

1 (3S)
 

1 (3X)
 

(27)
 

2 (7X)
 

1 iiSl _
 

# NUMbER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 * NUMBER OF ANIMALS NECROPSIED
 

63
 
TABLE C1. MALE RATS: NONNEOPLASTIC LESIONS (CONTINUED)

 

MATCHED
 

CONTROL LOW DOSE HIGH DOSE
 

ENDOCRINE SYSTEM
 

#PITUITARY (16) (1) (15)
 

CYST, NOS 2 (13%) 1 <7X)
 

#ADRENAL (30) (21) (33)
 

HiMORRHAGE 1 (3X)
 

ANGIECTASIS 1 (3JS) 3 (13X) 2 (6S)
 

*ADRENAL CORTEX (30) (2U) (33)
 

LIPOIDOSIS 11 (37X) 4 (17X) 1 (3X)
 

ATROPHY, NOS 1 (3«)
 

#PARATHYROID (25) C*) (24)
 

CYST, NOS 1 (4K)
 

HYPERPLASIA, NOS i* (16%)
 

REPRODUCTIVE SYSTEM
 

#PRO:>TATE (29) (2) (31)
 

INFLAMMATION, ACUTE 2 (7X)
 

INFLAMMATION, CHRONIC 4 (14%) 3 (10%)
 

*SEMINAL VESICLE (33) (33) (34)
 

DILATATION, NOS 1 (3%)
 

INFLAMMATION, CHRONIC 1 (3%)
 

ABSCESS, CHRONIC 1 (3S)
 

tTESTIS (32) (23) (31)
 

ABSCESS, NCS 1(3%)
 

PiRIARTERITIS 2 (6X)
 

CALCIFICATION, DYSTROPHIC 1 (4%)
 

ATROPHY, NCS 9 (28%) 12 (52%) 10 (32%)
 

ASPERMATOGENESIS 1 (3%) 1 (3%)
 

#TESTIS/TUBUIE (32) (23) (31)
 

ATROPHY, FCCAI 1 (495)
 

NERVOUS SYSTEK
 

#BRAIN (31) (29) (32)
 

ABSCESS, NOS 1 (3%)
 _ ACCESS,. CHRONIC l_i3Sl .. .
 

* NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

64
 
TABLE C1. MALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

SPECIAL SENSE ORGAN S 

*EYE

INFLAMMATION ,

*EYE/RETINA

INFLAMMATION ,

 ACUTE

 NOS

 (33)

 (33)

 (33)

 2

 (33)

 2

 (6X) 

 (6X)

 (34) 

 (3<J) 

1 (3%) 

HOSCULOSKELETAL SYSTEM 

NONi. 

BODY CAVITIES 

*MESENTEHY

PERIARTERITIS

 (33)

 1 (3X) 

 (33) (34) 

A LL OTHER SYSTEM S 

NONE 

SPECIAL MOREHCIOG Y SUMMAR Y 

NO LESION EEPOHTED

ACCIDENTAL DEATH

AUTO/NECROPSY/HISTO PERF 1 

AUTO/NECROESY/NO HISTO

AUTOLYSIS/NO NECROPSY 2

# NUMBER OF ANIMALS WITH TISSUE EXAHINED MICROSCOPICALLY 

* NUMBER OF ANIMALS NECROPSIED 

1 

2 

1 1 

1 

65
 
TABLE C2.

 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN FEMALE RATS 

ADMINISTERED 1,4-DIOXANE IN THE DRINKING WATER 

MATCHED
 

CONTROL LOW DOSE HIGH DOSE
 

ANIMALS INITIALLY IN STUDY 35 35 35
 

ANIHALS NECBOESIED 34 35 35
 

ANIMALS EXAMINED HISTOPATHOLOGICA LLY 31 34 32
 

INTEGUMENTARY SYSTEM
 

*SKIN (34) (35) (35)
 

EPIDERMAL INCLUSION CYST 1 (3X)
 

*SUBCUT TISSUE (34) (35) (35)
 

GKANULOMA, FOREIGN BODY 1 (3%)
 

RESPIRATORY SYSTEM
 

*NASAL TUKBINATE (34) (35) (35)
 

IwFLAMMATICN, HEHORHHAGIC 1 (3X)
 

INFLAMMATICN, ACUTE 1 (3X) 7 (20X) 2 (6X)
 

INFLAMMATION, ACUTE SUPPU8ATIVE 1 (3%) 16 (46X) 16 (46X)
 

INFLAMMATION, ACUTE/CHRONIC 1 (3X)
 

INFLAMMATION, CHRONIC 1 (3X)
 

fTRACHEA (29) (31) (24)
 

INFLABMATICN, NOS 5 (17X)
 

INFLAMMATION, ACUTE 2 (6X)
 

INFLAMMATION, ACUTE SUPPURATIVE 1 (3X) 5 (16X) 4 (17X)
 

INFLAMMATION, CHRONIC 1 (4X)
 

#LUNG/BHONCHOS (30) (34) (32)
 

INFLAMMATION, CHRONIC 1 (3X)
 

tLUNG (30) (34) (32)
 

CONGESTION, NOS 2 (7X)
 

INFLAMMATION, ACUTE SUPPURATIVE 1 (3X)
 

BBONCHOPNEUHONIA ACUTE SUPPURATI 4 (12X)
 

PNEUMONIA, CHRONIC HORINE 6 (20X) 5 (15X) 25 (78X)
 

INFLAMMATICN, CHRONIC SUPPUHATIV 1 (3X)
 

BRONCHOPNEUHONIA CHRONIC SUPPURA 2 (6X) 1 (3X)
 

GSANUL.QIJA.I £QS_ ._ .1 I3XJ.
 

f NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

66
 
TABLE C2. FEMALE RATS: NONNEOPLASTIC LESIONS (CONTINUED)

 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

HEMATOPOIETIC SYSTEM 

*BON£ MARRO W (31) (24) (20) 

HYPERPLASIA , HEHATOPOIETIC 4 (13%) 3 (13%) 1 (5%) 

#SPLEEN (30) (34) (32) 

HEMORRHAG E 1 (3%) 

INFLAMMATION , ACUTE 4 (13%) 1 (3%) 

INFLAMMATION , CHRONIC 1 (3%) 

HEHOSIDEROSIS 2 (7*) 6 (18%) 7 (22%) 

ATROPHY, NOS 1 (3%) 1 (3%) 

HEMATOPOIESIS 6 (20%) 7 (21S) 8 (25S) 

fMANDIBULA R I. NODE (25) (5) (5) 

HEMORRHA6IC CYST 1 (4%) 

INFLAMMATION , ACUTE 1 (U%) 

PLASMA-CELL INFILTRATE 3 (12%) 

HYPERPLASIA , LYMPHOI D 5 (20%) 3 (60S) 

INEStNTERIC L. NODE (25) (5) (5) 

HYPERPLASIA, LYMPHOID 1 (4%) 

#THYMUS (9) (3) (1) 

CYST, NOS 2 (22%) 

ATROPHY, NOS 9 (100%) 3 (100%) 1 (100%) 

CIRCULATORY SYSTE M 

#HEAHT (31) (34) (32) 

FIBROSIS 1 (3%) 

CALCIFICATION, DYSTROPHIC 1 (3%) 

#MYOCARDIU M (31) (34) (32) 

INFLAMMATION , CHRONIC 1 (3%) 

*HESENTERIC ARTER Y (34) (35) (35) 

THROMBOSIS, NOS 1 (3%) 

INFLAMMATION , CHRONIC 1 (3%) 

DIGESTIVE SYSTE M 

*LIVER (31) (33) (32) 

CONGEST IQIU.NOS !_13%.) ^ 

f NUMBER OF ANIMAL S WITH TISSUE EXAMINE D MICROSCOPICALLY 

* NUMriER OF ANIMALS NECROPSIED 

67 
TABLE C2. FEMALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE 

NECROSIS, NOS 

NiCROSIS, fOCAL 

NtCROSIS, EIFFOSE 

HbTAHORPHCSIS FATTY 

LIPOIDOSIS 

HYPERTROPHY. NOS 

HYPEEPLASIA, NOS 

ANGIECTASIS 

HEMATOPOIESIS 

1 (3X) 

1 (3X) 

2 (6») 

7 (23X) 

1 (3%) 

3

1

6

1

2

11

1

 (9X) 

 (3X) 

 (18X) 

 (3%) 

 (6X) 

 (33%) 

 (3%) 

#LIVER/CENTRILOBULAR 

METAMORPHOSIS FATTY 

(31) 

1 (3%) 

(33) 

*BIL£ DUCT 

DILATATION. NOS 

INFLAMMATION, CHRONIC 

HYPERPLASIA, NOS 

(3i») 

1 (3%) 

1 (3») 

13 (38%} 

(35) 

3 (9X) 

#PANCREAS 

INFLAMMATION WITH FIBROSIS 

(29) 

1 (3%) 

(15) 

#PANCREATIC EUCT 

HYPERPLASIA, NOS 

(29) 

3 (10%) 

(15) 

#PANCREATIC ACINUS 

ATROPHY, NOS 

(29) (15) 

#STOMACH 

EDEMA, NOS 

ULCER, ACUTE 

CALCIFICATION, DYSTROPHIC 

(31) 

1 (3%) 

(33) 

1 (351) 

#GASTRIC MUCOSA 

EfiOSION 

(31) (33) 

1 (3%) 

URINASY SYSTEK
 

f KIDNEY (31) (34)
 

MINERALIZATION 17 (55%) 12 (35%)
 

HuMATOMA, ORGANIZED
 

PYELONEPHRITIS, NOS 1 (3%)
 

PYELONEPHRITIS, ACUTE 1 (3«)
 

INFLAMMATION, CHRONIC 5 (16X) 2 (6X)
 

DEGENERATION, NOS 1 (3X)
 

NEPHROSJS^. NOS 1 J3X)
 

t NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

._
 

HIGH DOSE
 

3 (9X)
 

1 (3X)
 

2 (6X)
 

2 (68)
 

17 (53X)
 

1 (3X)
 

(32)
 

(35)
 

1 (3X)
 

5 (1«X)
 

(16)
 

(16)
 

1 (6X)
 

(16)
 

1 (6%)
 

(30)
 

1 (3X)
 

1 (3X)
 

(30)
 

(32)
 

15	 (47%)
 

1 (3%)
 

1 (3%)
 

68
 
TABLE C2. FEMALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

KKIDNEY/HEDULI A 

MINERALIZATIO N 

#KIDNEY/TUBUII 

DILATATION, NOS 

CYST, NOS 

DEGENERATION , NOS 

#URINAR Y BLADDER 

EDEMA, NOS 

INFLAHMATICN , NOS 

INFLAMMATION, ACUTE 

ENDOCHINE SYSTE M 

#PITUITAR Y 

CYST, NOS 

tt ADRENA L 

HEMORRHAG E 

ANGIECTASIS 

•ADRENAL COfiTJX 

LIPOIDOSIS 

HYPERPLASIA , NOS 

#THYROID 

CYSTIC FOLIICLES 

FOLLICULAR CYST, NOS 

HYPEHPLASIA, C-CELL 

REPRODUCTIVE SYSTEH 

*VAGINA 

INFLAMMATION , ACUTE 

fUTEBUS 

INFLAMMATION, ACUTE 

tUTEHUS/ENDOMETRIUM 

CYST, NOS 

INFLAMMATION , ACUTE 

INFLAMMATIONA _ACOTE_SUPPnRATIVE 

MATCHED 

CONTROL 

(31) 

1 (3X) 

(31) 

4 (13%) 

(25) 

1 (4X) 

1 (4X) 

(18) 

3 (17X) 

(30) 

15 (SOS) 

(30) 

9 (30X) 

2 (7%) 

(28) 

1 (4X) 

1 («X) 

3 (11X) 

(34) 

(30) 

2 (7X) 

(30) 

2 (7X) 

2 (7X) 

LOW DOSE 

(3«) 

4 (12S) 

(34) 

(8) 

(3) 

(32) 

9 (28X) 

(32) 

3 (9X) 

(20) 

(35) 

1 (3X) 

(34) 

(34) 

11 (32X) 

3 (9X) 

2_i6XL. . 

HIGH DOSE 

(32) 

1 <3X ) 

(32) 

2 (6S) 

10 (31X) 

(<» ) 

1 (25X) 

(2) 

(29) 

1 (3X) 

7 (24X) 

(29) 

1 (3%) 

(18) 

(35) 

(28) 

1 (4X) 

(28) 

4 (14X) 

1 (4X) 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICHOSCOPICALLY
 

* NUMBER OF ANIMALS NECBOPSIED
 

69
 
TABLE C2. FEMALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

HYPERPLASIA, NOS
 

#OVAHY/OVIDUC1
 

INFLAMMATION, ACUTE
 

tOVAKY
 

CYSTIC FOIIICLES
 

FOLLICULAR CYST, NOS
 

NEHVOUS SYSTEM
 

•BRAIN
 

HEMORRHAGE
 

NECROSIS, NOS
 

SPECIAL SENSE ORGANS
 

*EYE
 

INFLAMMATION, ACUTE
 

CATARACT
 

*EYE/RETINA
 

INFLAMMATION, NOS
 

*EYE/LACRIMAL GLAND
 

INFLAMMATION, ACUTE SUPPURATIVE
 

*HARDERIAN GLAND
 

ABSCESS, NCS
 

MUSCULOSKELETAL SYSTEM
 

*SKELETAL MUSCLE
 

GBANULOBA, FOREIGN BODY
 

BODY CAVITIES
 

*ABDOMINAL WALL
 

INFLAMMATION, CHRONIC
 

ALL OTHER SYSTEMS
 

HQNE __
 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

1 (3%) 

(30) (34) (28) 

1 (3«) 

(26) (23) (22) 

1 (4X) 

1 (4%) 2 (9X) 

(31) (31) (28) 

1 (48) 

1 (4X) 

(34) (35) (35) 

3 (9X) 

1 (3«) 

(34) (35) (35) 

21 (62X) 4 (11X.) 3 (9%) 

(34) (35) (35) 

1 (3«) 

(34) (35) (35) 

1 (3») 

(34) (35) (35) 

1 (3*) 

(34) (35) (35) 

1 (3X) 

f NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

70
 
TABLE C2. FEMALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

SPECIAL MORPHOLOG Y SUMMAR Y 

AUTO/NECBCESY/N O HISTO 

AUTOLYSIS/NO NECROPSY 

3

1 

1 3 

# NUMBER OF ANIMAL S WIT H TISSUE EXAMINE D MICRCSCOPICALLY 

* NUMBER OF ANIMAL S NECROPSIE D 

71 

APPENDIX D
 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS
 

IN MICE ADMINISTERED 1,4-DIOXANE
 

IN THE DRINKING WATER
 

73
 

TABLE 01.

 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN MALE MICE 

ADMINISTERED 1,4-DIOXANE IN THE DRINKING WATER 

MATCHED
 

CONTROL LOW DOSE HIGH DOSE
 

ANIMALS INITIALLY IN STUDY 50 50 50
 

ANIHALS NECROPSIED 49 50 49
 

ANIMALS EXAMINED HISTOPATHOLOGICALLY 1*9 50 49
 

INTEGUMENTARY SYSTEM
 

*SKIN (49) (50) (49)
 

ULCER, CHRONIC 1 (2X) 1 (2%)
 

ACARIASIS 2 (4S)
 

CALCIFICATION, DYSTROPHIC 1 (2X)
 

HYPERPLASIA, NOS 1 (2X)
 

RESPIRATORY SYSTEM
 

*NASAL TURBINATE (49) (50) (49)
 

INFLAMMATION, ACUTE 1 (255) 1 (2%)
 

POLYP 1 (2%)
 

#LUNG (49) (50) (47)
 

HtMORRHAGE 1 (2%)
 

INFLAMMATION, NOS 1 (2%) 9 (18%) 17 (36%)
 

INFLAMMATION, SUPPUHATIVE 1 (2%)
 

HYPERPLASIA, ALVEOLAR EPITHELIUM 1 (2%) 1 (2%)
 

HEMATOPOIETIC SYSTEM
 

#SPL_EN (48) (49) (43)
 

HEMORRHAGE 1 (2%)
 

HEMATOPOIESIS 1 (2%)
 

#LYMPH NODE (1) (2) (1)
 

HYPERPLASIA, RETICULUM CELL 1 (100%)
 

HYPERPLASIA, LYMPHOID 1 (50XJ
 

CIRCULATORY SYSTEM
 

((MYOCARDIUM (49) (50) (48)
 

INFLAMMATION^ CHRONI _ _ _ _ _ C _ _1 X2«l_
 

* NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 * NUMBER OF ANIMALS NECROPSIED
 

75
 
TABLE 01. MALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE 

DIGESTIVE SYSTE M 

#LIVjiR (49) (50) 

NECROSIS, NOS 2 (4X) 

HYPERPLASIA , NOS 2 (H%) 

HYPEHPLASIA , CYSTIC 1 (2») 

ANGIECTASI S 2 (4X) 

URINAK Y SYSTE M 

NON E 

ENDOCHIN E SYSTE M 

NONi 

REPRODUCTIV E SYSTEM 

*PREPDTIAL GLAND (49) (50) 

DILATATION, NOS 1 (2%) 1 (2%) 

CYST, NOS 1 (2%) 

INFLAMMATION , NOS 1 (2%) 

ABSCESS, NCS 1 (2%) 

INFLAMMATION, CHRONIC 1 (2%) 

INFLAMMATION , CHRONIC SUPPURATI V 1 (2%) 3 (6«) 

#TESTIS (49) (34) 

GEANOLOMA, SPERMATIC 1 (2%) 

NERVOUS SYSTEM 

NONE 

SPECIAL SENSE ORGAN S 

NON£ 

MUSCULOSKELETAL SYSTEM 

NON E 

* NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

HIGH DOSE 

(47) 

5 (11X) 

1 (2%) 

1 (2%) 

(49) 

3 (6%) 

2 (41) 

1 (2X) 

(35) 

76 
TABLE D1. MALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

EODY CAVITIES 

NON£ 

ALL OTHER SYSTEMS 

NON£ 

SPECIAL MORPHOLOGY SOMMAEY 

NO LESION REPORTE D 

AUTO/NECROPSY/HISTO PEEF 

AUTOLYSIS/N C NECROPSY 

29 10

1 

1

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY 

* NUMBER OF ANIMALS NECROPSIED 

7 

1 

77 
TABLE D2. 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN FEMALE MICE 

ADMINISTERED 1,4-DIOXANE IN THE DRINKING WATER 

ANIMALS INITIALLY IN STUDY


ANIMALS MISSING


ANIMALS NECRCPSIED


ANIMALS EXAMINED HISTOPATHOLOGICALLY


INTEGUMENTARY SYSTEM
 

NONE
 

RESPIRATORY SYSTEM
 

*NASAL TURBINATE


INFLAMMATION, ACUTE


INFLAMMATION, ACUTE SUPPURATIVE


POLYP


#TRACHEA


POLYP


#LUNG


INFLAMMATION, NOS


INFLAMMATION, ACUTE
 

ABSCESS, NOS
 

HYPERPLASIA, ALVEOLAR EPITHELIUM


HEMATOPOIETIC SYSTEM
 

tSPLEEN


INFLAMMATION, ACUTE
 

INFLAMMATION, CHRONIC
 

ATROPHY, NOS
 

HYPERPLASIA, LYMPHOID


HtMATOPOIESIS


#LYMPH NODE


HYPERPLASIA, LYMPHOID


IMESiiNTERIC L. NODE


INFLAMMATION, CHRONIC
 

CIRCULATORY SYSTEM
 

NQN£ _ _ _ _


MATCHED 

CONTROL LOW DOSE HIGH DOSE 

 50 50 50 

1 

 50 48 39 

 50 48 39 

 (50) (48) 

3 (6%) 

4 (8») 

1 (2%) 

(39) 

5 (13%) 

3 (8%) 

 (45) (41) 

1 (2%) 

(25) 

 (50)

 2 (4%)

 1 (2%)

 (47) 

 33 (VOX) 

1 (2%) 

(36) 

32 (89«) 

2 (6%) 

1 (3X) 

 (50)

 6 (12S)

 (46) 

2 (4%) 

1 (2X) 

(37) 

1 (3%) 

1 (3*) 

1 (3X) 

2 (5%) 

 (5)

 1 (20%) 

 (1) (4) 

1 (25%) 

 (5) (1) CO 

1 (2555) 

_ _ _ _ _ - . 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

78 
TABLE 02. FEMALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

_ _, 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

DIGESTIVE SYSTEM 

#LIVER 

ABSCESS, NOS 

NECROSIS, NOS 

METAMORPHOSI S FATTY 

LIPOIDOSIS 

HYPEfiPLASIA . NOS 

ANGIECTASI S 

(50) 

1 (2%) 

(48) 

1 (2%) 

2 (H%) 

1 (2%) 

1 (2%) 

1 (15S) 

H (B%) 

(37) 

2 (5%) 

tLIVuR/HEPAICCYTES 

NECROSIS, NOS 

(50) 

1 (2%) 

(48) (37) 

#PANCREA S 

DILATATION/DUCTS 

ABSCESS, CHRONIC 

LIPOGRANULCB A 

(26) 

1 (4») 

(30) 

1 (38) 

(19) 

1 (5X) 

1 (5% ) 

#PANCHEATIC

ATROPHY ,

 ACINU S 

 NO S 

(26) (30) (19 ) 

1 (5X) 

URINAfi Y SYSTE M 

#KIDNE Y 

LYMPHOCYTI C INFLAMMATOR Y

PLASMA-CEL L INFILTRAT E 

 INFILTR 

(50) 

2 (4% ) 

(48) 

2

1

 (4?) 

(21) 

(36) 

1 (3% ) 

#KIDNEY/GLOMEEULUS 

AMYLOIDOSIS 

(50) 

1 (2%) 

(48) (36) 

ENDOCfilNE SYSTE M 

NONii 

REPRODUCTIV E SYSTE M 

tUTEHU S 

HYDROMETR A 

HilMORRHAGI C CYST 

ABSCESS, CHRONI C 

(«9)

14 (8%) 

(46) 

1 (2%) 

1 (2%) 

1 (2%) 

(34) 

2 (6%) 

2 (6% ) 

#UTERUS/ENDCMETRIU M 

C.XSI.I fiQS 

(49) 

_ _

(46) 

 2.J15X1 . 

(34) 

_1 J3£l_ 

* NUMBER OF ANIMALS WITH TISSUE EXAMINED

* NUMBER OF ANIMALS NECROPSIED 

 MICROSCOPICALLY 

79 
TABLE 02. FEMALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

INFLAMMATION, ACUTE


INFLAMMATION, ACUTE SUPPURATIVE


INFLAMMATION, CHRONIC SUPPURATIV


HYPERPLASIA, DIFFUSE


HYPEHPLASIA, CYSTIC


#OVAHY/PAROVARIAN


ABSCESS, CHRONIC


#OVAHY


CYST, NOS


FOLLICULAB CYST, NOS


INFLAMMATION, ACUTE SUPPURHTIVE


NERVOUS SYSTEM
 

NONE
 

SPECIAL SENSE ORGANS
 

NONE
 

HUSCULOSKELETA1 SYSTEM
 

NONE
 

BODY CAVITIES
 

NONE
 

ALL OTHER SYSTEMS
 

ADIPOSE TISSUE
 

LIPOGRANULOtlA


SPECIAL MORPHOLOGY SUMMARY
 

NO LESION REPORTED


AjJIHAL MISSINGZNO	 NECROPSY


MATCHED
 

CONTROL LOW DOSE HIGH DOSE
 

3 (1%)
 

1 (3%)
 

1 (2%)
 

1 (2X)
 

 48 (98%) 26 (57%) 23 (68%)
 

 (49)	 (46) (34)
 

1 (2%)
 

 (20)	 (24) (20)
 

5 (25%) 8 (33X) 1 (5%)
 

5 (25%) 2 (8%)
 

1 (5X)
 

1
 

1 1 2
 

, 1 _ _ _ _, _ _
 

*	 NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

80
 
1 

TABLE D2. FEMALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

AUTO/NECRCFSY/HISTO PEHF 

AUTOLYSIS/NO NECROPSY 1 1 1 

* NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECHOPSIED
 

81
 

APPENDIX E
 

ANALYSES OF THE INCIDENCE OF PRIMARY TUMORS
 

IN RATS ADMINISTERED 1,4-DIOXANE
 

IN THE DRINKING WATER
 

83
 

85

 

Table El. Analyses of the Incidence of Primary Tumors in Male Rats
 

Administered 1,4-Dioxane in the Drinking Water3
 

High Dose Low High
 

Topography: Morphology Control Dose Dose
 

Integumentary System: Fibroma^5

 3/33 (9) 1/33 (3) 1/34 (3)
 

P Valuesc»d N.S.
 

Relative Risk (High Dose Control)f 0.324
 

Lower Limit 0.006
 

Upper Limit 3.787
 

Weeks to First Observed Tumor 96 101 110
 

Nasal Turbinate: Squamous-cell
 

Carcinomab 0/33 (0) 12/33 (36) 16/34 (47)
 

P Values

c»d P < 0.001
 

Relative Risk (High Dose Control)f Infinite
 

Lower Limit 5.028
 

Upper Limit Infinite
 

Weeks to First Observed Tumor 60 52
 
86

 

Table El. Analyses of the Incidence of Primary Tumors in Male Rats
 

Administered 1,4-Dioxane in the Drinking Water3
 

(continued) 

High Dose Low High 

Topography: Morphology Control Dose Dose 

Nasal Turbinate:
 

. Adenocarcinoma, NOSb 0/33 (0) 0/33 (0) 3/34 (9)
 

P Valuesc»d N.S.
 

Relative Risk (High Dose Control)f Infinite
 

Lower Limit 0.593
 

Upper Limit Infinite
 

Weeks to First Observed Tumor — 74
 

Liver: Hepatocellular
 

Adenoma or Carcinoma** 2/31 (6) 2/32 (6) 1/33 (3)
 

P Values0 »d N.S.
 

Relative Risk (High Dose Control)f 0.470
 

Lower Limit 0.008
 

Upper Limit 8.568
 

Weeks to First Observed Tumor 100 101 110
 
87

 

Table El. Analyses of the Incidence of Primary Tumors in Male Rats 

Administered 1,4-Dioxane in the Drinking Water3 

(continued)
 

High Dose Low High
 

Topography: Morphology Control Dose Dose
 

Adrenal: Pheochromocytoma^ 6/30 (20) 0/24 (0) 2/33 (6)
 

P Valuesc»d N.S.
 

Relative Risk (High Dose Control )f 0.303
 

Lower Limit 0.032
 

Upper Limit 1.545
 

Weeks to First Observed Tumor 86 110
 

Pituitary: Chromophobe Adenoma
 

or Adenoma, NOSb 3/16 (19) 0/1 (0) 1/15 (7)
 

P Valuesc»d N.S.
 

Relative Risk (High Dose Control)f 0.356
 

Lower Limit 0.007
 

Upper Limit 3.840
 

Weeks to First Observed Tumor 110 110
 
88

 

Table El. Analyses of the Incidence of Primary Tumors in Male Rats 

Administered 1,4-Dioxane in the Drinking Water3

 

(continued) 

Topography: Morphology

High Dose 

 Control 

Low

Dose

 High 

 Dose 

Thyroid: C-cell Adenomab 3/29 (10) 1/17 (6) 0/31 (0) 

P Valuesc»d N.S. 

Relative Risk (High Dose

Lower Limit 

Upper Limit 

 Control)

f 0.000 

0.000 

1.525 

Weeks to First Observed Tumor 110 96 

Thyroid or Thyroid Follicle: 

Follicular-cell Adenoma, 

Cystadenoma, NOS, or Carcinoma" 3/29 (10) 1/17 (6) 1/31 (3) 

P Values0 »d N.S. 

Relative Risk (High Dose Control)f 0.312 

Lower Limit 0.006 

Upper Limit 3.626 

Weeks to First Observed Tumor 97 96 85 
89

 

Table El. Analyses of the Incidence of Primary Tumors in Male Rats 

Administered 1,4-Dioxane in the Drinking Water3 

(continued)
 

High Dose Low High
 

Topography: Morphology Control Dose Dose
 

Parathyroid: Adenoma, NOSb 2/25 (8) 0/4 (0) 0/24 (0)
 

P Valuesc»d N.S.
 

Relative Risk (High Dose Control )f 0.000
 

Lower Limit 0.000
 

Upper Limit 3.421
 

Weeks to First Observed Tumor 110
 __ ——
 

Mammary Gland: Fibroadenoma" 0/33 (0) 2/33 (6) 0/34 (0)
 

P Valuesc»d N.S.
 

Relative Risk (High Dose Control )f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor 89
 
90

 

Table El. Analyses of the Incidence of Primary Tumors in Male Rats
 

Administered 1,4-Dioxane in the Drinking Watera
 

(continued) 

High Dose Low High 

Topography: Morphology Control Dose Dose 

Tunica Albuginea or Vaginalis: 

Mesothelioma, NOSb 2/33 (6) 4/33 (12) 5/34 (15) 

P Values

c

»d N.S. 

Relative Risk (High Dose Control)

f 2.426 

Lower Limit 0.432 

Upper Limit 24.040 

Weeks to First Observed Tumor 81 89 69 

Brain: Glioma, NOSb 0/31 (0) 0/29 (0) 2/32 (6) 

P Values

c

»d N.S. 

Relative Risk (High Dose Control)

f Infinite 

Lower Limit 0.291 

Upper Limit Infinite 

Weeks to First Observed Tumor — 92 
91

 

Table El. Analyses of the Incidence of Primary Tumors in Male Rats
 

Administered 1,4-Dioxane in Drinking Water3
 

(continued)
 

a

Dosed groups received average doses of 240 or 530 mg/kg per day in drinking water.
 

"Number of tumor-bearing animals/number of animals examined at site (percent). Controls were
 

matched to the high-dose only and no statistics are provided for the low-dose group.
 

c

Beneath the incidence of tumors in the high-dose group is the probability level for the Fisher
 

exact test for the comparison of that dosed group with its matched-control group when P < 0.05;
 

otherwise, not significant (N.S.) is indicated.
 

^A negative trend (N) indicates a lower incidence in a dosed group than in a control group.
 

e

The probability level for departure from linear trend is given when P < 0.05 for any comparison.
 

^The 95% confidence interval of the relative risk between the high-dose group and its control
 

group.
 
92

 

Table E2. Analyses of the Incidence of Primary Tumors in Female Rats
 

Administered 1,4-Dioxane in the Drinking Water3
 

Matched Low High
 

Topography; Morphology Control Dose Dose
 

Integumentary System: Fibroma'3 1/34 (3) 2/35 (6) 2/35 (6)
 

f Values0'd N.S. N.S. N.S.
 

Relative Risk (Matched Control )f 1.943 1.943
 

Lower Limit 0.106 0.106
 

Upper Limit 111.290 111.290
 

Weeks to First Observed Tumor 115 86 84
 

Nasal Turbinate: Squamous-cell
 

Carcinoma*5 0/34 (0) 10/35 (29) 8/35 (23)
 

P Values

c»d P = 0.008 P = 0.001 P = 0.003
 

Departure from Linear Trend6 P = 0.039
 

Relative Risk (Matched Control)b Infinite Infinite
 

Lower Limit 2.942 2.258
 

Upper Limit Infinite Infinite
 

Weeks to First Observed Tumor 69 66
 
93

 

Table E2. Analyses of

Administered

(continued) 

Topography: Morphology


All Sites: Hemangioma or
 

Hemangiosarcoma"


P Values0 »d


Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor


Liver: Hepatocellular Adenoma*5


P Valuesc>d


Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

 the Incidence of Primary Tumors in Female 

 1,4-Dioxane in

Matched
 

 Control
 

 0/34 (0)
 

 N.S.
 

—
 

 0/31 (0)
 

 P = 0.001
 

 the Drinking Water3 

Low
 

Dose
 

2/35 (6)
 

N.S.
 

Infinite
 

0.291
 

Infinite
 

86
 

10/33 (30)
 

P = 0.001
 

Infinite
 

2.860
 

Infinite
 

73
 

Rats 

High
 

Dose
 

3/35 (9)
 

N.S.
 

Infinite
 

0.593
 

Infinite
 

66
 

11/32 (34)
 

P < 0.001
 

Infinite
 

3.296
 

Infinite
 

70
 
__ 

94

 

Table E2. Analyses of the Incidence of Primary Tumors in

Administered 1,4-Dioxane in the Drinking Water3 

(continued) 

Matched Low
 

Topography: Morphology Control Dose
 

Pituitary: Chromophobe Adenoma
 

or Adenoma, NOSb 4/18 (22) 1/3 (33)
 

P Valuesc»d N.S. N.S.
 

Relative Risk (Matched Control)f 1.500
 

Lower Limit 0.033
 

Upper Limit 6.475
 

Weeks to First Observed Tumor 116 110
 

Thyroid: C-cell Adenoma*3 4/28 (14) 0/20 (0)
 

P Values0 »d P = 0.033(N) N.S.
 

Relative Risk (Matched Control)f 0.000
 

Lower Limit 0.000
 

Upper Limit 1.444
 

Weeks to First Observed Tumor 115
 

 Female Rats 

High
 

Dose
 

0/2 (0)
 

N.S.
 

0.000
 

0.000
 

4.985
 

0/18 (0)
 

N.S.
 

0.000
 

0.000
 

1.593
 

—
 
Table E2. Analyses of the Incidence of Primary Tumors in Female Rats
 

Administered 1,4-Dioxane in the Drinking Watera
 

(continued)
 

Topography; Morphology


Thyroid or Thyroid Follicle:
 

Cystadenoma, NOSb


P Valuesc»d


Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor


Mammary Gland: Adenoma or
 

Cystadenoma, NOSb


P Values0. d


Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor


Matched Low High 

 Control Dose Dose 

 2/28 (7) 1/20 (5) 1/18 (6) 

 N.S. N.S. N.S. 

0.700 0.778 

0.012 0.014 

12.385 13.643 

 116 111 92 

 3/34 (9) 4/35 (11) 1/35 (3) 

 N.S. N.S. N.S. 

1.295 0.324 

0.237 0.006 

8.246 3.798 

 113 73 84 

95

 
96

 

Table E2. Analyses of the Incidence of Primary Tumors in Female Rats
 

Administered 1,4-Dioxane in the Drinking Water3
 

(continued) 

Matched Low High 

Topography; Morphology Control Dose Dose 

Mammary Gland: Fibroadenomab 13/34 (38) 16/35 (46) 10/35 (29)
 

P Valuesc»d N.S. N.S. N.S.
 

Relative Risk (Matched Control )f 1.196 0.747
 

Lower Limit 0.645 0.344
 

Upper Limit 2.249 1.583
 

Weeks to First Observed Tumor 107 46 92
 

a

Dosed groups received average doses of 350 or 640 mg/kg per day in drinking water.
 

"Number of tumor-bearing animals/number of animals examined at site (percent).
 

c

Beneath the incidence of tumors in the control group is the probability level for the Cochran-


Armitage test when P < 0.05; otherwise, not significant (N.S.) is indicated. Beneath the
 

incidence of tumors in a dosed group is the probability level for the Fisher exact test for
 

the comparison of that dosed group with the matched-control group when P < 0.05; otherwise,
 

not significant (N«S=) is indicated.
 

d

A negative trend (N) indicates a lower incidence in a dosed group than in a control group.
 

e

The probability level for departure from linear trend is given when P < 0.05 for any comparison.
 

*The 95% confidence interval of the relative risk between each dosed group and the control group.
 
APPENDIX F
 

ANALYSES OF THE INCIDENCE OF PRIMARY TUMORS
 

IN MICE ADMINISTERED 1,4-DIOXANE 

IN THE DRINKING WATER 

97 

99

 

Table Fl. Analyses of

Administered

 the Incidence of Primary Tumors in

 1,4-Dioxane in the Drinking Water3 

 Male Mice 

Matched Low High 

Topography: Morphology Control Dose Dose 

Integumentary System: Fibrosarcoma^3 0/49 (0) 4/50 (8) 0/49 (0) 

P Valuesc » d N.S. N.S. N.S. 

Departure from Linear Trende P = 0.009 

Relative Risk (Matched Control)f Infinite — Lower Limit 0.909 — Upper Limit Infinite 

_— _ 

Weeks to First Observed Tumor — 77 

Lung: Alveolar/Bronchiolar Adenoma 

or Carcinomab 8/49 (16) 3/50 (6) 3/47 (6) 

P Valuesc « d P = 0.048(N) N.S. N.S. 

Relative Risk (Matched Control)f 0.368 0.391 

Lower Limit 0.066 0.070 

Upper Limit 1.430 1.516 

Weeks to First Observed Tumor 92 91 89 
100

 

Table Fl. Analyses

Administered

 of the Incidence of Primary Tumors

 1,4-Dioxane in the Drinking Wat

 in

er3 

 Male Mice 

(continued) 

Topography: Morphology

Matched 

 Control 

Low 

Dose 

High 

Dose 

Hematopoietic System: Lymphoma^ 0/49 (0) 5/50 (10) 2/49 (4)
 

P Valuesc»d N.S. P - 0.030 N.S.
 

Relative Risk (Matched Control)f Infinite Infinite
 

Lower Limit 1.237 0.296
 

Upper Limit Infinite Infinite
 

Weeks to First Observed Tumor — 77 91
 

All Sites: Hemangioma or
 

Bemangiosarcoma" 0/49 (0) 6/50 (12) 3/49 (6)
 

d
 P Values0

 » P = 0.047 P = 0.014 N.S.
 

Relative Risk (Matched Control) f Infinite Infinite
 

Lower Limit 1.569 0.602
 

Upper Limit Infinite Infinite
 

Weeks to First Observed Tumor 91 66
 
101

 

Table Fl. Analyses of

Administered

(continued) 

Topography: Morphology


Liver: Hepatocellular Carcinoma'3


P Valuesc»d


Relative Risk (Matched Control )f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor


Liver: Hepatocellular
 

Carcinoma or Adenoma^


P Valuesc»d


Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor


 the Incidence of Primary Tumors in

 1,4-Dioxane in the Drinking Water3 

Matched Low 

 Control Dose 

 2/49 (4) 18/50 (36) 

 P < 0.001 P < 0.001 

8.820 

2.287 

74.477 

 93 91 

 8/49 (16) 19/50 (38)
 

 P < 0.001 P = 0.014
 

2.328
 

1.086
 

5.517
 

 92 91
 

 Male Mice 

High
 

Dose
 

24/47 (51)
 

P < 0.001
 

12.511
 

3.406
 

101.955
 

58
 

28/47 (60)
 

P < 0.001
 

3.649
 

1.852
 

7.934
 

58
 
102

 

Table Fl. Analyses of the Incidence of Primary Tumors in Male Mice 

Administered 1,4-Dioxane in the Drinking Water3

 

(continued) 

a

Dosed groups received average doses of 720 or 830 mg/kg per day in drinking water.
 

"Number of tumor-bearing animals/number of animals examined at site (percent).
 

G

Beneath the incidence of tumors in the control group is the probability level for the Cochran-


Armitage test when P < 0.05; otherwise, not significant (N.S.) is indicated. Beneath the
 

incidence of tumors in a dosed group is the probability level for the Fisher exact test for
 

the comparison of that dosed group with the matched-control group when P < 0.05; otherwise,
 

not significant (N.S.) is indicated.
 

"A negative trend (N) indicates a lower incidence in a dosed group than in a control group.
 

e

The probability level for departure from linear trend is given when P < 0.05 for any comparison.
 

f
 

•"-The 95% confidence interval of the relative risk between each dosed group and the control group.
 
__ 

103

 

Table F2. Analyses of

Administered

Topography: Morphology

Lung: Alveolar/Bronchiolar Adenoma 

or Carcinomab

P Valuesc»d

Relative Risk (Matched Control^ 

Lower Limit 

Upper Limit 

Weeks to First Observed Tumor

Hematopoietic System: Lymphoma"

P Valuesc»d

Relative Risk (Matched Control)

f 

Lower Limit 

Upper Limit 

Weeks to First Observed Tumor

 the Incidence of Primary Tumors in

 1,4-Dioxane in

Matched 

 Control 

 3/50 (6) 

 N.S. 

 91 

 6/50 (12) 

 N.S. 

 76 

 the Drinking Water3 

Low 

Dose 

0/47 (0) 

N.S. 

0.000 

0.000 

1.766 

8/48 (17) 

N.S. 

1.389 

0.457 

4.501 

67 

 Female Mice 

High 

Dose 

3/36 (8) 

N.S. 

1.389 

0.196 

9.764 

81 

8/39 (21) 

N.S. 

1.709 

0.566 

5.457 

86 
104

 

Table F2. Analyses of the Incidence of Primary Tumors in Female Mice
 

Administered 1,4-Dioxane in the Drinking Water3
 

(continued) 

Matched Low High 

Topography: Morphology Control Dose Dose 

All Sites: Hemangioma or
 

Hemangiosarcoma" 2/50 (4) 4/48 (8) 0/39 (0)
 

P Values0 »d N.S. N.S. N.S.
 

Relative Risk (Matched Control)f 2.083 0.000
 

Lower Limit 0.314 0.000
 

Upper Limit 22.174 4.305
 

Weeks to First Observed Tumor 73 87 _«
 

Liver: Hepatocellular Carcinoma** 0/50 (0) 12/48 (25) 29/37 (78)
 

P Valuesc»d P < 0.001 P < 0.001 P < 0.001
 

Relative Risk (Matched Control)f Infinite Infinite
 

Lower Limit 3.822 13.395
 

Upper Limit Infinite Infinite
 

Weeks to First Observed Tumor — 82 83
 
105

 

Table F2. Analyses of the Incidence of Primary Tumors in Female Mice 

Administered 1,4-Dioxane in the Drinking Water3 

(continued) 

Matched Low High
 

Topography: Morphology Control Dose Dose
 

Liver: Hepatocellular
 

Carcinoma or Adenoma^3

 0/50 (0) 21/48 (44) 35/37 (95)
 

P Valuesc»d P < 0.001 P < 0.001 P < 0.001
 

Relative Risk (Matched Control)f Infinite Infinite
 

Lower Limit 7.102 17.510
 

Upper Limit Infinite Infinite
 

Weeks to First Observed Tumor — 82 81
 

a

Dosed groups received average doses of 380 or 860 mg/kg per day in drinking water.
 

^Number of tumor-bearing animals/number of animals examined at site (percent).
 

c

Beneath the incidence of tumors in the control group is the probability level for the Cochran-


Armitage test when P < 0.05; otherwise, not significant (N.S.) is indicated. Beneath the
 

incidence of tumors in a dosed group is the probability level for the Fisher exact test for
 

the comparison of that dosed group with the matched-control group when P < 0.05; otherwise,
 

not significant (N.S.) is indicated.
 

-A negative trend (N) indicates a lower incidence in a dosed group than in a control group.
 

e

lhe probability level for departure from linear trend is given when P < 0.05 for any comparison.
 

^The 95% confidence interval of the relative risk between each dosed group and the control group.
 

Review of the Bioassay of 1,4-Dioxane* for Carclnogenicity
 

by the Data Evaluation/Risk Assessment Subgroup of the
 

Clearinghouse on Environmental Carcinogens
 

March 7, 1978
 

The Clearinghouse on Environmental Carcinogens was
 

established in May, 1976, in compliance with DHEW Committee
 

Regulations and the Provisions of the Federal Advisory
 

Committee Act. The purpose of the Clearinghouse is to
 

advise the Director of the National Cancer Institute (NCI)
 

on its bioassay program to identify and to evaluate chemical
 

carcinogens in the environment to which humans may be
 

exposed. The members of the Clearinghouse have been drawn
 

from academia, industry, organized labor, public interest
 

groups, State health officials, and quasi-public health and
 

research organizations. Members have been selected on the
 

basis of their experience in carcinogenesis or related fields
 

and, collectively, provide expertise in chemistry, biochemistry,
 biostatistics, toxicology, pathology, and epidemiology.
 Representatives of various Governmental agencies participate
 

as ad hoc members. The Data Evaluation/Risk Assessment Subgroup
 

of the Clearinghouse is charged with the responsibility of
 

providing a peer review of reports prepared on NCI-sponsored
 

bioassays of chemicals studied for carcinogenicity. It is in
 

this context that the below critique is given on the bioassay
 

of 1,4-Dioxane for carcinogenicity.
 

The primary reviewer said that 1,4-Dioxane induced
 

squamous-cell carcinomas of the nasal turbinates in treated
 

rats and hepatocellular carcinomas in treated mice. He
 

briefly described the experimental design and conditions
 

under which 1,4-Dioxane was tested. In his critique, the
 

primary reviewer noted the poor survival among the rats
 

and the decreased water intake among the high dose treated
 

male mice. He said, however, that these shortcomings did
 

not effect the conclusion regarding the carcinogenicity
 

of 1,4-Dioxane.
 

The secondary reviewer questioned the significance
 

of the decreased water intake among the high dose treated
 

male mice. A Program staff member commented that the
 

mice may have increased their water retention as they
 

decreased their water intake. As a result, 1,4-Dioxane
 

may have concentrated in the animal urinary bladder.
 

107
 
It was pointed out that epidemiological studies have
 

shown an increased incidence of cancer of the nose and
 

related passages among furniture makers. A Subgroup member
 

noted that other studies have shown experimentally the
 

carcinogenicity of 1,4-Dioxane.
 

A motion was made that the report on the bioassay of
 

1,4-Dioxane be accepted as written. The motion was seconded
 

and approved unanimously.
 

Members present were:
 

Gerald N. Wogan (Chairman), Massachusetts Institute of
 

Technology
 

Arnold Brown, Mayo Clinic
 

E. Cuyler Hammond, American Cancer Society
 

Joseph Highland, Environmental Defense Fund
 

Henry Pitot, University of Wisconsin Medical Center
 

George Roush, Jr., Monsanto Company
 

Michael Shimkin, University of California at San Diego
 

*	 Subsequent to this review, changes may have been made
 

in the bioassay report either as a result of the review
 

or other reasons. Thus, certain comments and criticisms
 

reflected in the review may no longer be appropriate.
 

<tU.S. GOVERNMEN T PRINTIN G OFFICE ! 1978-260-899/3149
 

108
 

DHEW Publication No. (NIH) 78-1330