Comparison of conventional Pap smear and liquid-based cytology: A study of cervical cancer screening at a tertiary care center in Bihar

Abstract

Background: Cervical cancer is the fourth leading cause of cancer in women in the world and it is the second most common cancer in women 15-44 years of age. Strict implementation of screening programs has led to a large decrease in cervical cancer incidence and mortality in the developed countries. In contrast, cervical cancer remains largely uncontrolled in high-risk developing countries because of ineffective or no screening programs. Conventional Pap smear method has been the mainstay of most of the screening programs for many decades. However, this technique is not without limitations, and the sensitivity and specificity of cervical cytology are relatively low. To overcome the limitations of conventional Pap smear (CPS), liquid-based cytology (LBC) was introduced in 1990s as a better tool for processing cervical samples.

Objectives: This study was undertaken to compare CPS with liquid-based methods, to assess the effectiveness and feasibility of LBC over CPS in our setting, and also to evaluate the prevalence of human papillomavirus (HPV) in our population.

Materials and methods: This study was conducted in Gynecological Oncology Unit of Regional Cancer Center at Indira Gandhi Institute of Medical Sciences, Patna, Bihar. About 310 women were enrolled in this study and the sample was taken for both conventional cytology and LBC. The smears were studied in detail and were interpreted as per the Bethesda system of reporting Pap smears. The results were compared and analyzed statistically.

Results: Unsatisfactory smears were more commonly reported by conventional method (7.1%) than with liquid-based method (1.61%), and this difference is statistically significant. There was no difference in the detection of epithelial cell abnormalities using both the methods. HPV DNA for high-risk oncogenic strains (16 and 18) was detected in 6.45% of women in this study.

Conclusion: LBC has been found to be more superior to conventional smears only with respect to lesser number of unsatisfactory smears, but considering the economic implications of LBC, conventional Pap is more feasible in our setting.

Keywords: Cervical cancer screening; conventional Pap smear; human papillomavirus; liquid-based cytology.