Comparison of Liquid-Based Cytology and Conventional Papanicolaou Smear for Cervical Cancer Screening: An Experience From Pakistan

Introduction After the introduction of cervical cancer screening program with cervical cytology, a marked decline in deaths secondary to cervical cancer was observed in developed countries. Two methods are used for cervical cytology. The first one is the conventional Papanicolaou (PAP) and the second one is liquid-based cytology (LBC). Although various studies in western countries established the role of LBC in cervical cancer screening, no large-scale study was conducted in our population to compare the two techniques for cervical cancer screening. Therefore, in this study, we compared the diagnostic utility of these two techniques for detecting cervical epithelial lesions. Methods A total of 3,929 patients, who presented to the Gynecology Clinic, Liaquat National Hospital, for cervical cancer screening from January 2015 until December 2019, over a period of five years, were included in the study. A total of 1,503 specimens were prepared by LBC, and 2,426 specimens were prepared by a conventional PAP smear method. All smears were interpreted using the Bethesda System of Reporting Cytopathology. Results The mean age of the patients was 39.46±11.14 years. For cytological evaluation, 98.7% of specimens were adequate. The inadequacy rate was 1.3% for conventional PAP smear and 1.2% for LBC. While 97.2% of specimens were reported as negative for intraepithelial lesion or malignancy, 1.1% of specimens showed squamous epithelial lesions. There was a significant difference in the detection rate of squamous epithelial lesions using the two techniques. The detection rate of squamous intraepithelial lesions using LBC was 2.1%, which was higher than that of the conventional PAP smear (0.6%). The detection rates of glandular lesions using LBC and conventional PAP smear were 0.5% and 0.2%, respectively. Conclusion We found a higher disease detection rate of squamous epithelial lesions using LBC compared to conventional PAP smear. Therefore, we recommend a widespread use of LBC for mass cervical cancer screening in our population.