Interobserver Variability and Comparison of Liquid-Based Cytology Versus Conventional Pap Smear for Cervical Cancer...

Background and aim The conventional Pap smear (CPS), while long considered the most effective cervical cancer (CC) screening tool in India, has increasingly come under scrutiny for its validity and reproducibility. Liquid-based cytology (LBC) is a relatively newer technique that offers a cleaner background and fewer unsatisfactory smears. This study aimed to assess interobserver variability and compare the diagnostic accuracy of LBC and CPS in the CC screening of high-risk patients. Materials and methods Split smears for CPS and LBC were prepared from 402 high-risk patients. CPS slides were stained using the Papanicolaou method. All CPS and LBC slides were initially reviewed by one cytopathologist and subsequently reevaluated by a second cytopathologist, with reporting based on the 2014 Bethesda System. In cases of discrepancy, the final diagnosis was determined by a third, senior cytopathologist. Biopsy confirmation was available in 52 cases. Interobserver variation was assessed using Kappa (κ) statistics, while intraobserver variation (between CPS and LBC) was evaluated using Pearson's correlation coefficient (r). Results The strength of interobserver agreement was classified as very good for LBC (κ = 0.95) and good for CPS (κ = 0.79). Intraobserver agreement was high for observer 1 (r = 0.51) and moderate for observer 2 (r = 0.48). Diagnostic accuracy was 100% for LBC and 70% for CPS. CPS had significantly more unsatisfactory smears compared to LBC (p < 0.05). Conclusions Interobserver variability plays a critical role in diagnostic accuracy, patient care, and prognosis and has important medicolegal implications. In this study, interobserver variability was found to be higher in CPS than in LBC, highlighting LBC's greater reliability in CC screening among high-risk patients.