Abstract:
Background: Cervical cancer has high morbidity and mortality and in Kenya its second in
prevalence and first cause of cancer related mortality. Cervical cancer starts as cervical
dysplasia (cervical intraepithelial neoplasia (CIN)) which transform to invasion with time.
Early diagnosis of cervical dysplasia utilizes both colposcopy and histopathology.
Although histopathology is the gold standard for diagnosing cervical cancer, its access and
utility is limited due to both cost and limited expertise. There is also paucity of data on
sensitivity and specificity of colposcopy locally.
Objective: To determine the correlation between colposcopic and final histopathologic
results amongst patients undergoing a colposcopic evaluation in cervical dysplasia clinics
in Western Kenya.
Methods: This was a Cross sectional comparative diagnostic study conducted among 164
women undergoing Colposcopic evaluation across several cervical dysplasia clinics in
Western Kenya between august 2019 and august 2020. Institutional ethical approval was
sought and informed consent obtained from each participants. A colposcope was used to
examine the cervix and findings graded using the modified Reid‟s colposcopic index. A
colposcopy guided punch biopsy was then taken for histopathological evaluation when
abnormal area was sited. Descriptive statistical analysis of mean (with corresponding
standard deviation) for continuous variables and frequencies (with corresponding
proportions) for categorical variables was calculated to determine whether differences
across groups were statistically significant (p≤0.05). Bayesian theorem model was used to
determine the sensitivity, specificity, positive predictive value (PPV), and negative
predictive value (NPV) with corresponding 95% confidence interval. A Receiver Operating
Characteristics (ROC) curve was plotted as sensitivity against 1-specificity and the area
under the curve (AUC) computed. An overall Kappa value was calculated as an estimate of
the strength of correlation between colposcopy and histopathology.
Results: Mean age of the study participants was 40.6 years with 64.6% being HIV negative
and 134 (81.7%) were premenopausal. Modified Reid‟s index classified 20.7%, 40.2% and
39.1% as having low grade, intermediate and high-grade cervical dysplasia, respectively.
Colposcopy classified 0.6%, 38.4% and 60.1% as normal, CIN 1 and CIN 2/3 respectively.
Histopathology classified 16.5%, 26.2%, 53.3% and 3% as having Normal, CIN 1, CIN
2/3, Carcinoma in situ, respectively. Sensitivity of colposcopy with histology as gold
standard was 85.3%, specificity was 69.7% and diagnostic accuracy was 80.3%, Positive
predictive value (PPV) was 85.3% and Negative predictive value (NPV) was 69.7%. The
empirical ROC plot revealed an area under the curve with Optimal Youden‟s index value
of 0.7758. The estimated strength of correlation between colposcopy and biopsy was
relatively strong with kappa=0.55.
Conclusions: There were nearly equal proportions of intermediate and high-grade cervical
dysplasia when Modified Reid‟s index was used to classify colposcopy findings whereas
histopathology had more than half of all the findings classified as high grade disease
(CIN2/3). There is an association between the discriminatory powers of colposcopy and
histology but colposcopy had a lower specificity when compared to histopathology.
Recommendations: The study recommends that colposcopy is important in directing
biopsy, and histopathology should continue as a gold-standard for cervical cancer
diagnosis. Further studies to validate the findings especially controlling for the interobserver
variability are recommended.