10/2/05njm

**Q. How can I compare my facility's Pap result patterns to the national
average?**

A. Each lab should have a quality assurance process, but providers
should evaluate as well.

Effective screening for cervical cancer depends upon many variables.
Cervical cancer screening procedures have been improved in the past
decade through the development of new systems to increase compliance
with screening, improved techniques for obtaining and interpreting
cytological preparations, use of adjuvant HPV testing, and publication
of national screening and management guidelines.

The results of the Pap smear cannot be used to make a definitive
diagnosis or initiate treatment. Rather, the Pap smear functions solely
to screen for cellular abnormalities that are associated with an
increased risk for the development of cervical cancer. Thus, it selects
those women who should have further evaluation, such as colposcopy
and/or biopsy. Approximately 7 to 10 percent of women who are screened
require additional evaluation. Treatment decisions are then made based
upon diagnostic results from histologic examination, usually from
colposcopically directed biopsies.

#1

One good resource for such a comparison is Bethesda 2001 implementation
and reporting rates: 2003 practices of participants in the College of
American Pathologists Interlaboratory Comparison Program in
Cervicovaginal Cytology by Davey DD, Neal MH, Wilbur DC et. al

Here is an online table that shows a comparison from before and after a
large impact of liquid based sampling techniques.

Table 4.![](media/image1.png){width="0.1673611111111111in"
height="0.15555555555555556in"}Comparison of Reporting Rates for All
Specimens 1996 Versus 2002

![](media/image2.png){width="10.853472222222223in"
height="2.801388888888889in"}

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#2

You may want to also look at the age related prevalence in your cohort.
Here is an online table that shows the ASCUS Pap smears by age

Table 6.![](media/image1.png){width="0.1673611111111111in"
height="0.15555555555555556in"}Percent of Atypical Squamous Cells of
Undetermined Significance Cases Testing Positive for High-Risk Human
Papillomavirus (HPV) DNA

![](media/image3.png){width="5.240972222222222in"
height="3.1555555555555554in"}

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#3

**Overall screening program**

You may want to consider your sampling techniques as you evaluate your
overall cervical cancer screening program including a robust follow-up
program.

Cervical cytology screening programs can detect preinvasive, as well as
invasive, cellular changes of the cervix. Because cervical cancer
typically has a long preinvasive state (often a decade or more) and the
treatment for preinvasive disease is effective, screening programs
potentially can prevent the occurrence of invasive cervical cancer. For
example, most cases of invasive cervical cancer occur in women who have
either never been screened or have not been screened in the preceding
five years, thus losing the opportunity for detection of preinvasive
disease. Although cervical cancer accounts for relatively few deaths in
the United States, it is one of the leading causes of cancer death in
women in developing countries. This observation is thought to be
directly related to the lack of screening programs in those areas.

There are no randomized, controlled trials which demonstrate that
screening for cervical cancer decreases mortality or the incidence of
invasive disease. However, the large body of evidence accumulated from
observational studies provides supportive data that this is true. These
studies have compared the incidence rates of cervical cancer in regions
prior to and after the introduction of screening, or between areas with
different intensities of screening. In every case, the introduction of
cervical cancer screening was followed by a fall in the incidence of
invasive cervical cancer and cervical cancer deaths.

It is likely that there will be an increase in the use of liquid based
cytology and HPV DNA testing over the next five years. At this time,
neither the American Cancer Society nor the American College of
Obstetricians recommends use of any test over another. Patients and
providers should choose a method based upon factors such as the
patient\'s tolerance for false negative (higher with conventional Pap)
versus false positive tests (higher with liquid based cytology and HPV),
cost, and desired screening interval (combined testing is performed
every three years, liquid based screening every two years, and the
conventional Pap is done yearly).

**Sensitivity and specificity** --- Methodologic difficulties (eg,
different reference standards, lack of blinding, flaws in study design)
have made it difficult to determine the precise sensitivity and
specificity of the Pap smear. In studies that have compared normal
results for the conventional Pap smear with subsequent smears,
sensitivity ranges from 55 to 80 percent for high grade lesions.
Sensitivity as high as 90 percent was reported in a study that used cone
biopsy as the reference standard. In addition, moderate interobserver
interpretive variability exists for all types of cervical specimens (e.
g., cytology and histopathology), although lack of reproducibility is
greater for the least severe cytopathologic diagnoses. In studies that
used a second cytologist\'s review of the slide as the gold standard for
diagnosis of an abnormality, sensitivity (the ability to reliably
recognize abnormal cytology) was 70 to 80 percent. Thin layer technology
has been shown in multiple studies to significantly improve the
detection rate of high grade lesions when compared to conventional Pap
smears due to the improvement in slide preparation and the removal of
contaminants. The specificity of the Pap smear is probably above 90
percent for both conventional and liquid based tests.

Screening has been less effective for protection against development of
invasive adenocarcinoma. The lower sensitivity can be attributed to
several factors: it can be difficult for the cytopathologist to
distinguish between high-grade squamous cells and glandular cells;
endometrial cells, reactive endocervical cells, tubal metaplasia, and
cervical endometriosis may mimic adenocarcinoma in situ (AIS); and
lesions may not be seen or sampled because they are small and/or high in
the endocervical canal. However, recent data appear promising, possibly
due to improved screening techniques.

**Resources:**

**Bethesda 2001 implementation and reporting rates: 2003 practices of
participants in the College of American Pathologists Interlaboratory
Comparison Program in Cervicovaginal Cytology (see below)**

**Screening for cervical cancer, UpToDate**

<http://www.uptodateonline.com/application/topic.asp?file=gen_gyne/18631&type=A&selectedTitle=4~51>

**Management of the abnormal Papanicolaou smear, UpToDate**

<http://www.uptodateonline.com/application/topic.asp?file=gen_gyne/5367>

**Cervical intraepithelial neoplasia: Management, UpToDate**

<http://www.uptodateonline.com/application/topic.asp?file=gen_gyne/13946>

**Cervical intraepithelial neoplasia: Etiology, diagnosis, and natural
history, UpToDate**

<http://www.uptodateonline.com/application/topic.asp?file=gen_gyne/11845>

**Colposcopy, UpToDate**

<http://www.uptodateonline.com/application/topic.asp?file=gen_gyne/21852>

**Bethesda 2001 implementation and reporting rates: 2003 practices of
participants in the College of American Pathologists Interlaboratory
Comparison Program in Cervicovaginal Cytology**

CONTEXT: The 2001 Bethesda System for the reporting of cervical cytology
specimens and the use of new liquid-based and human papillomavirus
testing technologies have led to changes in cervical cytology reporting
practices. OBJECTIVES: To analyze current laboratory reporting practices
using Bethesda 2001 terminology and to compare results with previous
survey data from 1996. DESIGN: Questionnaire survey mailed to 1751
laboratories in mid-2003. PARTICIPANTS: Laboratories enrolled in the
College of American Pathologists Interlaboratory Comparison Program in
Cervicovaginal Cytology. RESULTS: Of the 759 responding laboratories,
most (85.5%) had implemented Bethesda 2001 terminology, and the majority
had adopted major changes, such as elimination of the benign cellular
changes category and the satisfactory but limited category. The median
reporting rate for low-grade squamous intraepithelial lesion was 2.1%,
compared to a 1996 median rate of 1.6%, but the increase was confined to
liquid-based preparations. Reporting rates for high-grade squamous
intraepithelial lesion (median, 0.5%) and atypical squamous cells (ASC)
had changed little. Most ASC cases were subclassified as \"undetermined
significance\" (median, 3.9%) with ASC, cannot exclude high-grade SIL
accounting for a minority (median, 0.2%). The median ratio of ASC to
squamous intraepithelial lesions and carcinomas (SIL+) was 1.4 and was
lower than the 1996 median ratio of 2.0. Median reporting rates for
squamous abnormalities for 2002 were noted to be significantly higher
for liquid-based preparations than for conventional smears, while median
ASC/SIL+ ratios were lower. Most laboratories offer human papillomavirus
testing, but almost half (47%) of laboratories do not know the
percentage of positive testing results in patients with ASC.
CONCLUSIONS: Most laboratories have implemented Bethesda 2001
terminology. New criteria and liquid-based methods have led to an
increase in low-grade squamous intraepithelial lesion reporting rates
and a decrease in ASC/ SIL+ ratios when compared with 1996 data.
Liquid-based preparations have higher median squamous intraepithelial
lesion rates and lower ASC/SIL+ ratios than conventional smears.

Davey DD, Neal MH, Wilbur DC et.al. Bethesda 2001 implementation and
reporting rates: 2003 practices of participants in the College of
American Pathologists Interlaboratory Comparison Program in
Cervicovaginal Cytology.  Arch Pathol Lab Med. 2004 Nov;128(11):1224-9.

Abstract

<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15504056&query_hl=1>

Full length article

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