Comparison between conventional Pap smear and liquid-based cytology in cervical cancer screening

Abstract

Purpose The present study aimed to compare between two techniques used for cervical screening: conventional Pap smear and liquid-based cytology (LBC). Patients and methods This study included 150 women referred from the early detection unit to the Cytopathology Unit, Pathology Department, NCI, Cairo University, for detection of cervical precancerous lesions. The ectocervix and endocervix were sampled using cytobrush, and the material was smeared on two glass slides and prepared for conventional smears. Rovers cervix-brush was used to collect samples for SurePath LBC, where the brush head was detached and dropped in the specific preservative-containing vial. Cytologic reporting was done according to the New Bethesda System 2014 for both preparations. Both qualitative and numerical data were calculated. Fleiss’ kappa was used to measure the agreement between both techniques. P value was calculated when required, which is considered significant if less than 0.05. Results Of the 150 included cases, 117 (78%) were satisfactory for evaluation with conventional preparation (CP), whereas 147 cases were satisfactory using liquid-based technique. The difference was found to be statistically significant. Endocervical cells were detected in 53/117 (45.3%) satisfactory cases of CP and in 84/147 (57.1%) satisfactory cases of LBC. Among the 117 satisfactory cases by both methods, CP can detect 49 (42%) cases with squamous or glandular lesions. On the contrary, in LBC, 41 (35%) cases showed epithelial abnormalities. The rate of atypical squamous cells of undetermined significance was lower in LBC (3%) compared with CP (7%). The glandular lesions were better detected in CP when compared with LBC (24 and 18%, respectively). The diagnosis of both preparations was different in 18 (12%) cases. In three (16.7%) cases, the diagnosis was upgraded by liquid based preparation (LBP), whereas a lower grade was given by LBP in 15 (83.3%) cases. Conclusion The rate of unsatisfactory cases was significantly reduced when LBC was used. LBC can be used for cervical cancer screening as CP, where there was a good agreement between their results.