Comparative analysis of manual liquid-based cytology and conventional Pap smear with p16 immunomarker application in premalignant and malignant cervical lesions

Background: Cervical carcinoma is the most common malignancy affecting the female reproductive tract. While conventional cervical smears stained with Papanicolaou (Pap) stain are widely used, they have relatively low sensitivity for detecting premalignant and malignant lesions. In recent years, liquid-based cytology (LBC) has emerged as a more effective screening method, offering higher sensitivity and the added advantage of utilizing residual material for ancillary tests such as immunocytochemistry. Among various immunomarkers, overexpression of p16 is a reliable indicator of cervical dysplasia and malignancy. Aim and Objectives: This study aims to compare the effectiveness of manual LBC (MLBC) with conventional Pap smear (CPS) techniques and to assess the diagnostic utility of p16 immunostaining in identifying premalignant and malignant cervical lesions. Materials and Methods: This study was conducted over a period of 24 months in the Department of Pathology at Raja Rajeswari Medical College and Hospital, Bangalore. A total of 80 cervical samples were collected and evaluated using CPS and MLBC methods. Results: Among the 80 cervical samples analyzed, MLBC demonstrated a significantly higher rate of satisfactory smears and superior detection of low-grade squamous intraepithelial lesions, high-grade squamous intraepithelial lesions, and invasive carcinoma compared to CPS. Importantly, all four cases of squamous cell carcinoma showed strong p16 immunopositivity. Conclusion: MLBC enhances sample adequacy and reduces the incidence of unsatisfactory smears. In addition, p16 immunostaining proves to be a valuable adjunct in the detection and confirmation of premalignant and malignant cervical lesions.