Diagnostic Value of Cytology and Colposcopy in Patients withAbnormal Cervical Pap Smears


Background: An optimal cancer detection system
for preclinical cervical lesions should combine a
cytological examination with a colposcopic follow-up
examination. Detection at early pre-invasive stage
provides an opportunity for treatment to prevent
progression to invasive cancer.
Objective: The present study aimed at evaluation
of cytology, colposcopy, and combined cytology and
colposcopy in predicting histopathological diagnosis
of cervical intraepithelial neoplasia/squamous
intraepithelial lesion (CIN/SIL) or other neoplastic
changes in patients with abnormal cervical
cytological findings.
Methods: This prospective study was conducted in
the Cyto-colposcopy Unit of Teaching Laboratories
and Outpatient Department of Medical City Teaching
Hospital over a period of one year (Sep. 2001- Sep.
2002). Eighty-one married females were included in
the study. A cervical smear was taken followed by a
colposcopic examination of the cervix and then a
punch biopsy was taken from the suspected lesions
for histopathological study. Estimation and evaluation
of the validity parameters of cytology, colposcopy,
and combined cytology and colposcopy were
performed using different cutoff points by special
statistical analysis.
Results: Sensitivity, specificity and accuracy of
cytology in the diagnosis of CIN/SIL were 73%,
93.2% and 84.0% respectively.
The False–negative rate was 27%. Sensitivity,
specificity and accuracy of colposcopy in the
diagnosis of CIN were 83.3%, 58.5% and 70.1%
respectively choosing doubtful findings as a cut-off
point. The combination of cytology and colposcopy
gave the following results: sensitivity, specificity and
accuracy were 94.6%, 61.4% and 76.5% respectively;
the negative predictive value (NPV) was 93.1%.
When suspicious colposcopic findings were chosen as
the cut-off point, the specificity and the positive
predictive value (PPV) were higher at the expense of
sensitivity and NPV
Conclusion: The conventional Pap smear, a
valuable tool in the evaluation of patients with
abnormal cervical cytology, was found to be of
relatively low sensitivity in predicting CIN/SIL.
Colposcopy is a valuable tool too. However, the
validity parameters showed variable figures
depending on the different cut-off points applied for
the diagnosis of CIN/SIL. The ideal cut-off point was
when doubtful and higher-grade colposcopic lesions
are considered positive. The combination of cytology
and colposcopy resulted in an increased sensitivity
and NPV. The specificity could be further increased
or improved when the threshold was set to distinguish
higher-grade lesions (suspicious lesions) from lesser
Key words: Colposcopy, Abnormal Pap smears,