Evaluation of adjunctive tests for cervical cancer screening in low resource settings.

ABSTRACT

BACKGROUND: Visual inspection of cervix after application of acetic acid (VIA) is an effective screening tool for cervical cancer in low resource settings, but its low specificity leads to high referral rates. Adjunctive testing may overcome this drawback. AIMS: This pilot study was aimed to assess test performances of VIA, human papillomavirus (HPV) testing and Pap smear, individually and in simulated combinations, to determine the probable best screening option. SETTING AND DESIGN: Gynecology outpatient department (OPD); cross-sectional study. MATERIALS AND METHODS: One hundred women with complaints of irregular vaginal bleeding or discharge, post coital bleeding or unhealthy cervix on examination underwent Pap smear, HPV testing, VIA, colposcopy and biopsy, if indicated, in this screening order. STATISTICAL ANALYSIS: Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for each of the tests with a biopsy result of > or =HSIL taken as the gold standard. Simulated parallel and sequential combinations for VIA/Pap, VIA/HPV and HPV/Pap were calculated and compared with individual test performance. RESULTS: Prevalence of abnormal Pap smears was 5%, VIA positive 51% and HPV positive 16%. Sensitivity and specificity of VIA were 100% and 53.3% respectively. For HPV and Pap tests corresponding figures were 85.7%, 89.7% and 50%, 98.9% respectively. The best simulated combination with a balance of sensitivity and specificity was of VIA followed by HPV testing (sensitivity 85.7%, specificity 95.4%). CONCLUSION: Addition of HPV testing to VIA can increase the specificity of VIA, thereby reducing the referral rates without compromising the sensitivity of the test.