National Cancer Institute

CARCINOGENESIS

Technical Report Series

January 1976

REPORT ON THE CARCINOGENESIS

BIOASSAY OF TECHNICAL GRADE

CHLORDECONE (KEPONE)

CAS No. 143-50-0

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

Public Health Service

National Institutes of Health

REPORT ON CARCINOGENESIS BIOASSAY OF

TECHNICAL GRADE CHLORDECONE (KEPONE)

CARCINOGENESIS PROGRAM, DIVISION OF CANCER CAUSE AND PREVENTION

NATIONAL CANCER INSTITUTE

January 1976

CONTRIBUTORS: This report presents a synopsis of results of a

carcinogenesis bioassay conducted by the Carcinogen Bioassay and Program

Resources Branch, Carcinogenesis Program, Division of Cancer Cause and

Prevention, National Cancer Institute (NCI), Bethesda, Maryland. This

research was conducted at the Gulf South Research Institute, New Iberia,

Louisiana, initially under direct contract to the NCI and from November

1, 1974, as a subcontract to Tracor Jitco, Incorporated, Prime Contractor

for the NCI Carcinogenesis Bioassay Program.

The results of this study were reviewed and this report was prepared

by Drs. C. Cueto, Jr.1 , N. P, Page! and U. Saffiottil. The experimental

design, including dose levels were determined by Drs. R. R. Bates1

and T. E. ShellenbergerM w ith the assistance of Drs. J. Η. Weisburger1»

2

and E. K. Weisburgeri; Principal Investigator for the contract and super

visor of the experiments was Dr. H. P. Burchfield3; chemical analysis

was performed by Dr. E. E. Storrs3: animal treatment and observations

were supervised by Dr. W. E. Greer3 with the technical assistance of

Mr. G. J. Eldrige3, Ms. D. H. Monceaux3 and Ms. D. Broussard3; the pathology

was conducted by Drs. E. E. Bernal3 and B. Burrato3; pathology was reviewed

by Drs. R. M. McCullyb, C. N. Barron5 and R. A. Squirei; statistical

analyses were performed by Dr. K. C. Chu1.

A detailed technical report is in preparation which will provide details

of the design, materials and methods used, conduct and results of the

study.

1 - Carcinogenesis Program, Division of Cancer Cause and Prevention,

National Cancer Institute, National Institutes of Health, Bethesda,

Maryland.

2 - Now with the Naylor Dana Institute for Disease Prevention, American

Health Foundation, Hammond House Road, Valhalla, New York.

3 - Gulf South Research Institute, Atchafalaya Basin Laboratories,

Post Office Box 1177, New Iberia, Louisiana.

4 - Now with the National Center for Toxicological Research, Jefferson,

Arkansas.

5 - Tracor-Jitco, Incorporated, 1776 E. Jefferson Street, Rockville,

Maryland.
REPORT ON CARCINOGENESIS BIOASSAY OF

TECHNICAL GRADE CHLORDECONE (KEPONE)

Carcinogenesis Program, Division of Cancer Cause and Prevention

National Cancer Institute

January 1976

ii

Summary: A carcinogenesis bioassay of technical grade chlordecone

(Kepone) was conducted using Osborne-Mendel rats and B6C3F1 mice.

Chlordecone was administered in the diet for 80 weeks at two dose

levels, with the rats sacrificed at 112 weeks and the mice at 90 weeks.

The starting dose levels were 15 and 30 ppm for male rats, 30 and 60 ppm

for female rats, 70 ppm for male mice and 40 and 80 ppm for female

mice. As these dose levels were not well tolerated, the dose levels

were reduced during the course of the experiment such that the average

dose levels were as follows: 8 and 24 ppm for male rats, 18 and 26

ppm for female rats, 20 and 23 ppm for male mice and 20 and 40 ppm

for female mice. Clinical signs of toxicity were observed in

both species including generalized tremors and dermatologic

changes. A significant increase (P< .05) was found in the incidence

of hepatocellular carcinomas of high dose level rats and of mice

at both dose levels of chlordecone. The incidences in the high

dose groups were 7% and 22% for male and female rats (compared with

0 in controls for both sexes) and 88% and 47% for male and female

mice (compared with 16% for male room controls and 0 in females);

for the low dose groups of mice the incidences were 81% for males

and 52% for females. In addition, the time to detection of the

first hepatocellular carcinoma observed at death was shorter for

treated than control mice and, in both sexes and both species,

it appeared inversely related to the dose. In chlordecone-treated

mice and rats extensive hyperplasia of the liver was also found.

The incidence of tumors other than in the liver for chlordeconetreated groups did not appear significantly different from that

in controls
I. INTRODUCTION:

Chlordecone is the common name for the chlorinated insecticide,

decachlorooctahydro-l,3,4-metheno-2H-cyclobuta(cd)pentalen-2-one,

which is commercially available under the trade name of Kepone.

The compound, first introduced in 1958, has been used as an

insecticide against leaf-eating insects, ants and cockroaches,

and as a larvicide against flies.

The testing of chlordecone is a part of the carcinogenesis bioassay

of a series of halogenated chemicals, including many pesticides,

present in the general and occupational environment of humans.

Chlordecone was selected for inclusion in this series because of

its chemical structure, its use, and its stability.

II. MATERIALS AND METHODS:

Chemical - The material used was technical grade chlordecone,

in the hydrate form. The compound was purchased as a single lot

from City Chemical Company, New York, New York, and was manufactured

by Allied Chemical Company, Houston, Texas. The purity of the

product was determined by the Gulf South Research Institute (GSRI)

Chemistry Department. Other than chlordecone, the other major

material was determined to be water involved in the hydration of the
carbonyl group. The GSRI gas chromatographic analysis (electron

capture detector) showed chlordecone as roughly 92% of the

total peak area which agrees with the manufacturer's assay

of the batch used. With a flame ionization detector, the

chlordecone peak represented about 98-99% of the total peak area.

Gas chromatographic analysis with either electron capture

or flame ionization detector showed at least two small unidentified

contaminants, together totalling 1.5-1.8% of the total peak area.

Chlordecone readily hydrates on exposure to room temperature

and humidity, and is normally used as a mono- to tri-hydrate (1).

Further analysis and purification of the technical material was

not attempted.

Dietary Preparation - All diets were formulated using finely-ground

Wayne rat laboratory feed to which was added the required amount of

chlordecone for each dietary level. Small amounts of acetone were

used as an aid to uniformly disperse the test compound in the feed.

The diets were mechanically mixed to assure homogeneity and to

allow for evaporation of the acetone. Each final formulated diet,

including the control, contained 2% corn oil, purchased from

a commercial distributor and produced by Opelousas Refinery Company,

Opelousas, Louisiana, added primarily as a dust suppressant. No

chemical analysis was made of the corn oil. Water and the

formulated diets were made available ad libitum to the experimental

animals and were replaced three times per week.
Animals - The Osborne-Mendel rat, procured from Battelle-Memorial

Institute, Columbus, Ohio, and the B6C3F1 hybrid mouse (C57B1/6

female χ C3H/He male), procured from Charles River Breeding

Laboratories, Incorporated, Cambridge, Massachusetts, were used

in this study. Upon receipt, both species were quarantined for

7-10 days, determined to be free from observable disease or

parasites, randomly assigned to experimental groups, and started

on treatment at approximately 6 weeks of age.

Animal Husbandry - All animals were housed in air-conditioned,

temperature and humidity-controlled rooms. Chlordecone was the only

compound under test in the room where the rats were housed, while

the mice were housed in a room where toxaphene, chlordane and

chlordecone were concurrently under test. Rats were maintained

in individual suspended wire cages, and mice were housed in plastic

cages with filter caps, five per cage for female, two-three per cage

for males. Clean cages for both species and filter caps for mouse

cages were provided weekly. Absorbent sheets under the rat racks

were changed three times per week. Cages on individual racks as

well as racks within the room were rotated on a weekly basis to

minimize potential position effects.

Clinical and Pathology Examinations - All animals were observed for

signs of toxicity twice daily and weights were recorded on a monthly

basis. Those appearing moribund at time of clinical examination

3
were sacrificed and necropsied. In the chronic study, the following

tissues were taken from sacrificed animals and, where possible, from

animals found dead: brain, pituitary, lymph nodes (cervical and

mesenteric), thyroid, parathyroid, salivary glands, lung, heart,

diaphragm, stomach (pylorus and fundus), duodenum, jejunum or ileum,

large intestine, pancreas, adrenal gland, kidney (longitudinal and

transverse), liver, skin, entire gonads, bladder, prostate or uterus,

and femur with marrow. Tissues were preserved in 10% buffered

formalin, embedded in paraffin, sectioned, stained with hematoxylin

and eosin, and microscopically examined.

Histopathological examination and diagnosis were conducted at

GSRI. A review of the pathology findings was conducted by

pathologists at Tracor Jitco, Inc., with special attention

given to liver lesions. National Cancer Institute pathologists

also reviewed several of the liver lesions.

Data Recording and Statistical Analysis - Pertinent data on

this experiment were recorded in an automatic data processing

system known as the Carcinogenesis Bioassay Data System (2).

The data elements, as recommended by the International Union

Against Cancer (UICC) (3), include details on the chemical, the

animals, experimental design, clinical observations, survival,

monthly weights, and individual pathology results· Data

4
tables were generated for statistical analysis and inclusion

in the report following pathology review and verification of data

transcription. The statistical analysis of tumor incidence

reported in Table II was performed using the Fisher Exact

Test (4a) to compare the controls to each dose level. A

correction for simultaneous comparison of controls was made using

the Bonferroni inequality (5). Thus, a corrected Ρ value < 0.05

was deemed significant. In addition, the Armitage test for linear

trend in proportions (4b) was used. This analysis determines

if the slope of a dose-response plot is statistically different

from zero (P < 0.05), assuming a linear trend. If the associated

statistic, which detects departure from linear trend, was not

significant (P > 0.05) and the Armitage statistic was significant

(P < 0.05), the latter Ρ value was reported in Table II.

Design of Chronic Studies - Preliminary toxicity studies were

conducted to obtain an estimated maximum tolerated dose (MTD) for

the long-term (80 weeks) administration of chlordecone in the diet.

These studies consisted of treating the animals for 6 weeks with

various dose levels of chlordecone and observing them for

an additional 2 weeks. Based primarily upon survival and weight

gain (as compared to controls) the estimated MTD's were calculated

as 30 ppm for male rats, 60 ppm for female rats and 40 and 80 ppm

for male and female mice respectively. As can be seen from Table I,

these dose levels were overestimated and they were found not to

5
be adequately tolerated, necessitating reductions at least once

in all groups. Actual dose levels and days on treatment at

each level are presented in Table I. A "time weighted average

dose" has also been calculated for each group and is Included

in Table I. Treatment with chlordecone was for 80 weeks with

sacrifice of all survivors by 90 weeks in the case of nice and

112 weeks for rats.

Ill, RESULTS:

A, Rats

· Survival - As presented in Table IIf the survival at

terminal sacrifice (112 weeks) for both males and females

at the high dose levels is considerably less than controls

and it appears treatment-related. Survival at other time

intervals during the study are also presented in Table II.

2. Clinical Signs - During the first 4 months of the study

the appearance and behavior of the low level animals were

generally comparable with the controls· Some high level

males during this period experienced epistaxis and bleeding

of the eyes, and 4 animals had died or were sacrificed. At

week 5 a majority of the high level females experienced

generalized tremors along with a slight drop in food
consumption. Many of the treated animals also showed a

loss of body weight. At week 28 many low level females

were experiencing generalized tremors. Body weights of this

group increased slightly during this period but food consumption was normal. Adverse clinical signs in all treatment

groups were noted at a low or moderate incidence during the

remainder of the first year, with a gradually increasing

frequency in treated animals during the second year of the

study. These signs included rough hair coats, dermatitis,

anemia and tremors. Some treated females showed evidence

of vaginal bleeding. Surviving animals at termination of

study generally exhibited a very poor physical condition.

3. Pathology - In the rats, two types of tumors were found:

neoplastic nodules and hepatocellular carcinomas. The

neoplastic nodules were composed of altered cell populations

appearing to arise de novo in the liver without evidence

of necrosis or fibrosis. There was compression of adjacent

parenchyma along at least part of the border of the nodule.

Within the nodule, there was abnormal plate arrangment

although cell plates were usually only one cell layer thick.

The cells within the nodule ranged from basophilic to

eosinophilic or clear, with one type predominating or

occasionally a mixture. Mitotic figures were occasionally

present.

7
The hepatocellular carcinomas were large, poorly circumscribed

masses. There were isolated islands of hepatocytes enveloped

by sinusoidal lining cells, abnormal liver plates» two or

more cells in thickness and arranged in bizarre histologic

patterns. On occasion, pseudoglandular formation was observed.

The cells were generally basophilic with varying degrees of

nuclear atypia and some mitotic figures. All carcinomas

were well-differentiated; no vascular invasion nor metastases

were observed in the material examined. Table II gives the

incidence of hepatocellular carcinomas and their statistical

analysis.

For female rats, a significant hepatocellular carcinoma

induction was found 10/45 at high dose, compared with 0/100

controls). For male rats, 3/44 high dose rats had hepatocellular

carcinomas as compared to 0/10 matched controls, and the

difference was not statistically significant at the 955£

confidence level. However, hepatocellular carcinomas are rare

in Osborne-Mendel rats and when the pooled control group is

used (0/105) the difference is statistically significant

(P < 0,05). These data are displayed in Figure 1.

Neoplastic nodules were diagnosed in 2 low dose r^ e rats,

with none in controls nor in the high dose group, and in

8
2 high dose female rats, with 1 in the matched controls

and none in the low dose group. Extensive liver hyperplasia,

fatty infiltration and degeneration were also found in rats

of both sexes in both dose groups. No liver hyperplasia was

seen in the matched control groups.

With the exception of liver tumors, the tumors in treated

and control groups did not differ significantly in type

and incidence. Table III presents all tumors by anatomic

site.

B. Mice

1. Survival - A reduction in survival occurred in treated

male mice as compared to the controls (Table II). In

contrast, the survival of treated females was comparable

to that of controls with most liver tumors found at

terminal sacrifice.

2. Clinical Signs - During the first year of the study, the

appearance and behavior of the low level males and females

and the control mice were generally comparable. Alopecia

(generalized and/or localized), sores on the tail and rough

hair coats were evident, especially among the males, apparently

due to fighting. In contrast, the high level female group

9
developed generalized tremors during the first week of the

study which persisted until terminal sacrifice; however3 the

intensity decreased in the majority of animals toward the end

of the study. Some individual mice in the high male group had

severe tremors which did not appear to affect body weight or

food intake. Approximately 20% of this high male group were

highly excitable during the second year. Bloating or abdominal

distention was noted first in the high level males at week 45

and in the high level females beginning at week 68. Also

during the second year several high level males and a few low

level males had palpable masses (nodules) in the abdominal

area.

3 · Pathology - The hepatocellular tumors in mice were all well

differentiated. They varied from well demarcated nodules

which compressed adjacent parenchyma to large masses which

both compressed and extended into adjacent liver. Within

the tumors, there were abnormal plate arrangements including,

in some, trabecular patterns several cell layers thick.

The tumor cells were usually basophilic, sometimes with

hyperchromatic polymorphic nuclei. There was little cellular

anaplasia and mitotic figures were variable in number. No

vascular invasion nor metastases were observed in the material

examined.

10
All these tumors were classified as hepatocellular carcinomas.

Their incidence and statistical analysis are given in Table II.

They were detected in 39/48 male mice at the lower dose and

in 43/49 males at the higher dose, as well as in 26/50 female

mice at the low dose and in 23/49 females at the high dose.

An abnormally high incidence was found in the matched control

group of male mice (6/19). In the 30 other control male mice,

kept in the same room, only 2 hepatocellular carcinomas (8%)

were found, the usual rate observed for this strain of mouse.

Pooling all these control groups results in an overall incidence

of 8/49 (16%). These data are displayed in Figure 2. In addition,

decrease in the time to first tumor detection was noted in male

mice at necropsy in both dose groups as compared to matched

or room controls (Table II). Statistical analysis indicated a

significant incidence of hepatocellular carcinomas at both dose

levels of both male and female mice.

In addition to hepatocellular carcinomas, extensive liver

hyperplasia was found in male and female mice in both high

and low dose groups. A few matched controls of each sex

also had liver hyperplasia although the incidence was quite

low as compared to the treated groups.

Other than liver tumors, no other tumor type appeared in

significant numbers as illustrated in Table IV.

11
IV. DISCUSSION:

The results of this study clearly suggest that technical grade

chlordecone, as administered under the test conditions described,

induced hepatocellular proliferative lesions, including

hepatocellular carcinomas, in both sexes of rats and mice.

The term "hepatocellular carcinoma11 was used to diagnose proliferative

lesions of the livers in mice which, in the judgment of the

pathologists, had the potential or the capacity for progressive

growth, invasion, metastasis and for causing death of the host.

This judgment was based upon the cytologic and histologic features

of the neoplasms and the knowledge that lesions with the same

morphologic characteristics as those observed have exhibited

malignant biologic behavior.

The terms "neoplastic nodule" and "hepatocellular carcinoma" used

to diagnose proliferative liver lesions in rats were based upon

the morphologic criteria and nomenclature recently reported

from a workshop on the classification of specific hepatocellular

lesions in rats (6).

The schedule of treatment and sacrifice involved administration

of the test compound for only 80 weeks followed by an observation

period of 10 weeks in mice and 32 weeks in rats. The tumors

found at terminal sacrifice were therefore observed well after

12
termination of treatment, but their potential spread and

dissemination during the natural lifespan of the animals could

not be evaluated because the observations were cut off

at 90 weeks for mice and 112 weeks for rats.

In regard to the animal models, the Osborne-Mendel rat was chosen

because of the experience gained by the Food and Drug Administration

where this strain has been used for many years as a general

purpose test animal. In addition, it was found sensitive to the

carcinogenicity of CC14 by subcutaneous injection (7). However,

the Osborne-Mendel rat was refractory to the induction of liver

cancer by N-2-Fluorenylacetamide (FAA) (8), Data on susceptibility

of various rat strains have been reviewed (9). The B6C3F1 strain

of mice has been extensively used by NCI for carcinogenesis bioassays,

Current experience in the NCI Program indicates an overall incidence

of hepatocellular carcinomas reported in control mice of 7-10%

in males and approximately 1% in females. For male mice, the

matched controls, but not the other room controls, showed an

abnormally high incidence. Although with the strict procedures

used for diet preparation, a mixup in feed appears highly improbable,

the possibility of environmental contamination of the controls

cannot be ruled out. Even so, the increase in hepatocellular

carcinomas in male mice at both dose levels was statistically

significant (P < .01) using either pooled or matched controls.

As we expected, no spontaneous hepatocellular carcinomas were

13
seen in rat controls of either sex nor in the female mouse controls,

The significant response in the female mouse and both male and

female rats is consistent with and reinforces the findings in

the male mice.

The material used was considered adequately pure with no more than

2% impurities other than water. Chlordecone is normally available

and used in a hydrated form. It is conceivable that a minor

impurity could contribute to the carcinogenic response observed

for the technical product but only further studies with a more

purified material could settle this question.

A concern in any testing program is the possible influence of

extraneous factors. As two other compounds were on test with

mice in the same room the possibility of a low level exposure

in the air must be considered. As all of the compounds are

low in volatility, the use of filtered, fully-enclosed animal .

cages restricted the potential for cross-contamination. As rats

were maintained in a room restricted only to the chlordecone

experiment, such potential cross-contamination from other test

compounds should not be of concern in this case.

The methodology used in these studies varied somewhat from current

NCI procedures (10) in that: (a) the subchronic toxicity testing

period was for 42 rather than 90 days; (b) the treatment period

14
was for 18 months rather than 24 months; and (c) the number of

matched controls was 10-20 rather than 50 as is currently used.

It is felt that in spite of these differences this experiment remains

useful as a screening test for carcinogenicity. The shorter

subchronic toxicity test did not accurately predict the maximum

tolerated doses and as a result, dose levels had to be reduced

during the course of the experiment. A 24-month exposure period

might have induced an even greater response, especially in rats,

than was found in this experiment. The use of pooled controls,

and particularly room controls, compensates for the small numbers

of matched controls· The response in all groups but the male rat

was significant (P < .05) even using the small matched control

groups.

Changes in dosage of chlordecone during the study were required

to avoid toxic effects. For this reason, and because the basic

design includes only two dose levels, a quantitative assessment

of dose response relationships is not possible.

15
REFERENCES

1. Martin, Hubert (Ed.): Pesticide Manual, British Crop Protection

Council, p 90, 2nd Edition, 1971.

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

Peters, J. A.: Carcinogenesis Bioassay Data System. J. Comp.

Biomed. Res. 7: 230-248, 1974.

3. Berenblum, I. (Ed.): Carcinogenicity Testing. UICC Technical

Report Series, Volume Y. Geneva, Switzerland, International

Union Against Cancer, 1969, 56 pp.

4. Armitage, P.: Statistical Methods in Medical Research, J. Wiley

and Sons, New York, 1971. (a) p 135, (b) p 363.

5. Miller, R. 6., Jr.: Simultaneous Statistical Inference, McGrawHill New York, 1966, p 8.

6. Squire, R. A. and Levitt, M. H.: Report of a Workshop on

Classification of Specific Hepatocellular Lesions in Rats.

Cancer Res. 35: 3214-3233, 1975.

7. Reuber, M. D., Glover, E. L.: Cirrhosis and Carcinoma of the

Liver in Male Rats Given Subcutaneous Carbon Tetrachloride,

J. Natl. Cancer Inst., 44: 419-423, 1970.

8. Symeonidis, A.: Tumors Induced by 2-Acetyl amino-fluorene in

Virgin and Breeding Females of Five Strains of Rats and in their

Offspring. J. Natl. Cancer Inst. 15: 539, 1954.

9. Weisburger, John H. and Weisburger, Elizabeth K.: VII. Tests

for Chemical Carcinogenesis. Busch, Harris (Ed.): Methods in

Cancer Research, New York, London, Academic Press, 1967,

Volume 1, pp. 307-398.

10. Sontag, J., Page, N., and Saffiotti, U.: Guidelines for

Carcinogen Bioassay in Small Rodents. NCI Carcinogenesis

Technical Report No. 1 (In Preparation).

16
Table I, Dosage Schedule - Concentration of Chlordecone 1n Feed

SPECIES

Rat

(OM)

Mice

(B6C3F1)

SEX

F

F

F

F

DOSAGE

GROUP

Low

High

Low

High

Low

High

Low

High

DOSE

Initial

Final

Initial

Intermediate

Final?

Initial

Intermediate

Final

Initial

Intermediate

Final

Initial

Intermediate

Final

Initial

Final

Initial

Intermediate

Final

Initial

Intermediate

Final

CONCENTRATION

IN FEED

(PPM)

15

5

30

10

10

30

15

5

60

30

10

40

20

10

40

20

40

20

10

80

40

20

TREATMENT

PERIOD

(DAYS)

147

413

386

99

75

220

166

174

42

344

174

134

161

265

90

470

134

161

265

134

161

265

TIME WEIGHTED

AVERAGE DOSE1

(PPM)

8

··

24

18

„

26

e—

20

23

_

20

40

NOTES: 1 Time-weighted average dose « Ζ (dose concentration χ treatment period in days)/ Σ (no. days receiving each dose

2 This group received Chlordecone on alternate weeks only during the final 75 days of treatment. Time

weighted average dose was calculated using only the days an animal received a dose.
TABLE II . Carcinogenesis Bioassay o f Chlordecone (Technical Grade - Kepone)

00

SPECIES

Rat

(OH)

Mouse

(B6C3F1)

SEX

F

F

F

F

F

F

F

F

DOSE1

Control?

Control*

Low

High

g

Control ControrQ

Low

High

Control1°

Contror

Low

High

Control1°

Contror

Low

High

EFFECTIVE*

NUMBER

105

10

50

44

100

10

49

45

49

19

48

49

40

10

50

49

PERCENT SURVIVAL

52

„

100

96

84

mm

100

86

84

mm

100

96

90

100

98

96

WEEKS

Ί8Γ".

90

90

60

90

78

72

__

95

80

54

„«.

100

94

92

TERM.

63

90

60

42

61

70

56

40

92

90

58

50

85

90

84

84

ANIMALS WITH HEPATOCELLULAR CARCINOMAS

TIME TO4

TUMOR

(WEEKS)

112

• 108

mm

..

87

83

87

87

70

62

_..

87

76

NUMBER

0

0

1

3

0

0

1

10

8

6

39

43

0

0

26

23

c

PERCENT5

0

0

2

7

0

0

2

22

16

32

81

88

0

0

52

47

 VALUES6

MATCHED

CONTROLS

1.000

1.000

1.000

.2181

.0000*

,0004#

.00001

—

.00311

.00811

POOLED

CONTROLS

.0034*

.6452

.0490# *

.6577

.00001

.0000*

.0000#

.0000#

--

.00001

.00001

NUMBER

OTHER

TBA

NA**

3

21

14

NA**

6

25

20

NA**

0

1

0

NA**

0

0

2

NOTES: 1 See TABLE 1 for actual dosage and for schedule of dosage changes.

2 Total number of animals initially placed on test minus number missing or autolyzed.

3 Termination of study: 112 weeks for rats and 90 weeks for mice.

4 Time to detection of first hepatocellular carcinoma at necropsy.

5 Percent of animals with hepatocellular carcinoma based on EFFECTIVE NUMBER of animals used.

6 One-tail Ρ value determined by the Fisher Exact Test for 2 χ 2 contingency table of control versus dose level with correction for use

of simultaneous comparison of control unless otherwise stated. # - Statistically significant (P < .05). * - One-tall Ρ value from

Armitage test for linear trend 1n proportion is highly significant, and Ρ > .05 for departure from linearity.

7 Animals with tumors other than liver.

8 Pooled controls with birthdate within 3 months of matched controls and maintained In different rooms from treated animals during the study.

9 Matched controls for females; pooled controls for males with 1/2 matched for each dose.

10 Pooled controls with birthdate within 4 months of matched controls· and maintained in same room as treated animals.

NA** Exact number not available at present.
TABLE III. Number of Rats with Tumors by Anatomic Site (Chlordecone)

EFFECTIVE NUMBER OF ANIMALS

ANIMALS WITH TUMORS

INTEGUMENTARY SYSTEM

SUBCUT. TISSUE

LEIOMYOSARCOMA

SKIN

FIBROMA

RESPIRATORY SYSTEM

LUNG

ALVEOLAR/BRONCHIOLAR CARCINOMA

DIGESTIVE SYSTEM

LIVER

HEPATOCELLULAR CARCINOMA

NLOPLASTIC NODULE

HEMANGIOMA

SARCOMA, NOS

ΜΥΕΙΟΜ

LIVER/BILE DUCT

HAMARTOMA

PAPILLARY ADENOMA (BILE DUCT ONLY)

BILE DUCT ADENOMA (BILE DUCT ONLY)

CECUM

LEIOMYOSARCOMA

URINARY SYSTEM

KIDNEY

MIXED TUMOR MALIG.

URINARY BLADDER

PAPILLOMATOSIS

ENDOCRINE SYSTEM

PITUITARY

CHROMOPHOBE ADENOMA

ADENOCARCINOMA

THYROID

FOLLICULAR-CELL CARCINOMA

FOLLICULAR-CELL ADENOMA

C-CELL ADENOMA

C-CELL CARCINOMA

PARATHYROID

ADENOMA

PANCREATIC ISLETS

ISLET-CELL ADENOMA

ADRENAL

CORTICAL ADENOMA

HEMATOPOIETIC SYSTEM

SPLEEN

HEMANGIOMA

BONE MARROW

MYELOMA

MULTIPLE ORGAN

LEUKEMIA GRANULOCYTIC

RETICULUM-CELL SARCOMA

CONTROLS

1O(1OOX)

3( 30%)

2(40%)

2(40%)

2

MALES

LUOOSE

50(100%)

24( 48X)

1(2%)*

1(2%)

1

4(8%)

4(8%)

1

2

1

20(40%)

12(24%)

12

9(18%)

3

2

3

1

1(2%)

1

1(2%)

1(2%)

1(2%)

HIGH DOSE

44(100%)

16( 36%)

 V

1(2%)

1(2%)

1

5(11%)

3(7%)

3

2(5%)

1

1

1(2%)

1

2(5%)

1(2%)

1

1(2%)

1

7(16%)

6(14%)

5

1

1(2%)

1

1(2%)

1

2(5%)

1(2%)

3(2%)

CONTROLS

10(100%)

7( 70%)

1(10%)

1(10%)

1

3(30%)

3(30%)

3

FEMALES

LOW DOSE

49(100%)

29( 59%)

5(10%!

3(6%)

1

2

2(4%)

1

1

16(33%)

13(27%)

13

3(6%)

1

2

1(2%)

1(2%)

1(2%)

1

HIGH DOSE

45(100%)

31( 69%)

1(2%)

1(2%)

1

19(42%)

15(33%)

10

2

1

2

4(9%)

4

9(20%)

4(9%)

3(7%)

1

1

2(4%)

2

2(4%)

2(4%)

1

1

1

COLUMNS ARE OFFSET ACC0R0IH6 TO ORGAN SYSTEM, SPECIFIC ORGAN AND TUMOR TYPE.

19

(Percentages by System and by Organ Are Based on the Effective Number of Animals)
TABLE III . Number of Rate with Tumors by Anatomic Site (Chlordecone) (Continued)

(Percentages by System and by Organ Are Based on the Effective Number of Animals)

REPRODUCTIVE SYSTEM

MAMMARY GLAND

FIBROADENOMA

ADENOMA

FIBROMA

AiirNOCARCINOMA

FIBROLIPOMA

UTERUS

ENDOMETRIAL/STROMAL POLYP

MALIG. LYMPHOMA

UTERUS/MYOMETRIUM

SQUAMOUS-CELL CARCINOMA

OVARY

ARRHENOBLASTOMA

GRANULOSA-CELL TUMOR

CERVIX UTERI

SQUAMOUS-CELL CARCINOMA

NERVOUS SYSTEM

PERIPHERAL NERVE

NEURILEMOMA

MUSCULOSKELETAL SYSTEM

SKELETAL MUSCLE

SARCOMA

SPECIAL SENSE ORGANS

EYE

NEURILEMOMA MALIG.

ALL OTHER SYSTEMS

MULTIPLE ORGAN

SQUAMOUS-CELL CARCINOMA

CONTROLS

1(20*)*

1(?O*)

1

MALES

LUITDOSE

1(2*)

1(2*)

1

HIGH DOSE

2(5*)

2(5*)

1

1

CONTROLS

5(50*)

5(50*)

4

2

Hio*)

1(10*)

FEMALES

LOW DOSE

13(27*)

7(14*)

4

1

2

4(8*)

1

1(2*)

1(2*)

1(2*)

1(2*)

1(2%)

1(2*)

HIGH DOSE

5(11*)

2(4*)

1

1

1(2*)

1(2*)

1

1(2*)

1

1(2*)

1(2*)

COLUMNS ARE OFFSET ACCORDING TO ORGAN SYSTEM, SPECIFIC ORGAN AND TUMOR TYPE.

20
TABLE IV. Number of M-tce with Tumors by Anatomic Site (Chiordecone)

(Percentages by System and by Organ Are Based on the Effective Number of Animals)

EFFECTIVE NUMBER OF ANIMALS

ANIMALS WITH TUMORS

RESPIRATORY SYSTEM

LUNG

ALVEOLAR/BRONCHIOLAR ADENOMA

DIGESTIVE SYSTEM

LIVER

HEPATOCELLULAR CARCINOMA

CECUM

HEMANGIOMA

URINARY SYSTEM

URINARY BLADDER

TRANSITIONAL-CELL CARCINOMA

HEMATOPOIETIC SYSTEM

MULTIPLE ORGAN

ACUTE LYMPHOCYTIC LEUKEMIA

REPRODUCTIVE SYSTEM

OVARY

CYSTAOENOMA

CONTROLS

19(100%)

6( 31%)

6(31*)

6(31%)

6

MALES

LOW DOSE

48(100%)

39( 81%)

39(81%)

39(81%)

39

1(2%)

1(2%)

1

HIGH DOSE

49(100%)

43( 88%)

2(4%)*

2(4%)

2

43(88%)

43(88%)

43

CONTROLS

10(100%)

0( 0%)

FEMALES

LOW DOSE

50(100%)

27( 54%)

26(52%)

26(52%)

26

1(2%)

1(2%)

.1

HIGH DOSE

49(100%)

25( 51%)

24(49%)

23(47%)

23

1(2%)

1

1(2%)

1(2%)

1

COLUMNS ARE OFFSET ACCORDING TO ORGAN SYSTEM, SPECIFIC ORGAN AND TUMOR TYPE.

21
22

Figure 1. Comparison of Incidence of Hepatocellular Carcinoma

(Chlordecone)

PERCENTAGE OF ANIMALS WITH HEPATOCELLULAR CARCINOMA
Figur

e 2. Comparison of Incidence of Hepatocellular Carcinoma

(Chlordecone)

PERCENTAGE OF ANIMALS WITH HEPATOCELLULAR CARCINOMA

23


DHEW Publication No. (NIH) 76-1278