PART ONE
General Cytology
access is the consequence of the inequality in the quality of the
services. Past failures of cervical screening in developing coun-
tries are attributable to failures in program quality, rather than
to technological limitations of the screening test.28,29
It is very important to evaluate the efficacy of the programs in
reducing the disease, and also whether the screening approach
chosen is cost effective, before considering extending imple-
mentation to large populations. A screening program is justified
if a prior diagnosis that permits a cost-effective and measurable
reduction of the disease is made.
Design of Screening Programs
Cervical cancer can be avoided when there is an early diagnosis
of the precursor lesions, without local or systemic compromise.
The implementation of a systematic program of prevention of
gynecological cancer among women in British Columbia in
1949 reduced both the incidence and the mortality caused by
this neoplasia. Among the methods available for early detection
of cervical cancer, exfoliative cytology, or the Pap test, is recom-
mended worldwide for mass screening, because the efficacy in
the detection of premalignant lesions, associated with the social
role of the method, permits minimization of costs with curative
medicine.1,4,6-8,13,15,30
From that stated above, a routine of procedures essential to
the success of a program of prevention may be obtained. The
basic integrated actions include: (1) care with collection, (2)
processing of the smears, (3) screening and interpretation of
the specimens, (4) follow-up of the patients, and (5) quality
control.31 1
2
3
1.
Care with collection
—The majority of false-negatives
arise from problems with collection of specimens,
and for this reason this stage should be systemized
and there should be training and recycling of the per-
sonnel responsible for taking the samples. The smears
must be well identified, slim, uniform, and without
contaminants, and contain samples from the trans-
formation zone, where in the majority of cases the
cervical cancer develops. There should be a minimum
of blood, mucus, or other obscuring material such as
lubricating gel. It is also important at this moment to
adequately fix the material so as not to compromise
subsequent stages.
2.
Processing the specimens
—In general prevention pro-
grams cover a large number of tests, so laboratories
should have guidance regarding the systemizing of
the processing and the recording of a large volume of
specimens. One of the characteristics of the Pap test
is that it consists of various stages. Each stage should
be monitored so as to minimize the possibility of
error. The condition on arrival of the slides, and the
number of slides per case, must be verified. Special
care should be taken with the flow of the tests, with
adequate numbering and balanced coloration with
control of the number of cases colored in each set.
The end product of this stage will be fundamental to
a good result with the rest.
3.
Screening and interpretation of the specimens
—The
screening should be done in as little time as pos-
sible, depending on the basic requirements of each
program, by trained and qualified personnel. Care
should also be taken with excess workloads for
cytopathologists and cytotechnicians, and also
with refresher courses and recycling. The report on
the tests should be systemized and use a unique
nomenclature, of which all involved in the prepara-
tion and interpretation of the results should be
fully aware.
4.
Follow-up of patients
—The prevention program should
include reference, contra-reference, and active search
services. The mere detection of the lesions will not
determine the impact on the natural history of the
disease. For this reason the treatment of lesions in a
pre-invasive stage is fundamental. Outpatient treat-
ment centers for the more simple cases, and others
for more complex cases should be integrated into
a service network for the program. Mechanisms for
finding and managing patients who did not return
after the initial test and who show alterations
are fundamental for a prevention program to
function well.
5.
Quality control
—Quality is fundamental in
gynecological cytopathology. One of the greatest
problems in mass cytology is the false-negative
cases. Cytopathology labs must have mechanisms
for internal quality control with the objective of
avoiding false-negative and false-positive tests. These
mechanisms should include measures relating to
the screening and interpretation of the specimens,
a review of 10% of the cases seen by the cytotechni-
cian, grouping the technicians according to hierar-
chy. External quality control must be included in
the design of the prevention program, conducted by
an accredited entity and with interlab action with
the objective of guaranteeing the homogeneity and
quality of the laboratory procedures.32 It should also
function as a detector of eventual problems and
could indicate a need for redirectioning continuous
education efforts within the program. For additional
information on quality assurance in cytopathology
see Chapter 4.
Cancer screening may be offered to a population either as
an organized program or opportunistically, or as some combi-
nation of the two. Opportunistic screening is spontaneous and
initiated either by the individual or healthcare provider during
routine healthcare encounters. It is often associated with low
coverage of people at high risk and excessive repetition of proce-
dures at frequent intervals, high costs, and a small benefit at the
population level. Systematic or organized screening programs
refer to planned and concerted public health application of
early detection and treatment in defined populations, operating
under precise protocols and guidelines.33
Some countries with organized screening programs can
reduce the incidence of cervical cancer by up to around 80%
in areas with high-quality screening, good coverage, and a reli-
able follow-up. Organized programs with systematic call-up,
recall, follow-up, and vigilant systems have shown more expres-
sive effects with less resources than less organized programs.34
Various alternative screening strategies are being researched for
developing countries, although the challenge in less-developed
countries is surpassed by the complex array of problems that go
far beyond the introduction of simplified technology.35
50
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