Comparison of visual inspection of cervix and Pap smear for cervical cancer screening

Abstract

Objective: To evaluate the performance of visual inspection of cervix (VIA) after application of 3% acetic acid in cervical cancer screening in comparison with Pap smear.

Design: Comparative study.

Place and duration of study: This study was conducted at Sir Ganga Ram hospital, Lahore, from January 1996-December 1999.

Subjects and methods: Speculum examination was carried out to see the cervix in 501 women. All subjects were screened simultaneously by Pap smear and VIA after application of 3% acetic acid. Positive cases by both screening methods and grossly abnormal cervix even with negative screen were subjected to colposcopy. In case of colposcopic abnormality of atypia or advanced lesions, biopsies were taken. Histology of colposcopically directed biopsy was taken as gold standard to evaluate the performance of the test.

Results: Out of 540 subjects, 356 were negative with both screening techniques. One hundred and fifty-six subjects were positive with VIA(28.9%) while Pap smear was positive in seventy-eight subjects (14.4%). The sensitivity of VIA was 93.9% and of Pap smear was 46.9%. Corresponding specificities were 30.4% and 69.5%. There was no significant difference between the positive predictive value (PPV) of both test (p < 0.05). The accuracy of VIA was 77.5% compared to 52.8% of Pap smear. The difference was highly significant (p < 0.01).

Conclusion: These results indicate that VIA is more sensitive and has a higher accuracy as compared to Pap smear. It could, therefore, be valuable in detection of precancerous lesions of cervix. Low cost, easy applicability and immediate results make VIA a useful screening test in developing countries like Pakistan as compared to Pap smear.