Evaluation of cytology as secondary triage in visual inspection after application of 4% acetic acid-based cervical cancer screening program

Abstract

Abstract Context (Background): Visual-based screening techniques are low cost and have good sensitivity. Hence, they appear promising for primary screening in low-resource settings. However, to reduce referrals for diagnostic colposcopy, there is need to triage these screen-positive women with test with good specificity. Aims: The study aims to evaluate the performance of cytology as triage for visual inspection after application of 4% acetic acid (VIA) screen-positive women. Settings and Design: Community-based cervical cancer screening using VIA was implemented among socioeconomically disadvantaged women in Mumbai, India. Methods: Cytology was performed on screen-positive women. All primarily screen-positive women underwent colposcopy. Directed biopsies were obtained among women with positive findings on colposcopy. The gold standard used for final disease status was histopathology or negative colposcopy. Statistical Analysis Used: Test characteristics of cytology as triage test. Results: Among the 138,383 population, 16,424 eligible women were screened with VIA. 785 (4.78%) women were VIA positive and 580 women participated in triage with cytology. The sensitivity and specificity of cytology at threshold of atypical squamous cells of undetermined significance in detecting ≥cervical intraepithelial neoplasia (CIN) 2 were 75.0 and 94.7, respectively. The positive and negative predictive values of cytology as triage test were 23.1 and 99.4, respectively, and the false positivity and false negativity rates were 5.34 and 25.0, respectively. Conclusion: Cytology triage with VIA can reduce referrals for colposcopy to 4.97% of original referrals but may miss around 25%, of high-grade CIN. The substantial reduction in referrals has special implication for low-resource settings, wherein compliance to referral and availability of diagnostic facilities are poor.