Colposcopic and histopathologic comparative interpretations among patients undergoing evaluation for cervical dysplasia in Western Kenya

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.