Adjunctive testing for cervical cancer in low resource settings with visual inspection, HPV, and the Pap smear

Objective: To test whether the performance of visual inspection using acetic acid (VIA) could be improved through adjunctive testing and to determine whether the combination of visual inspection of the cervix and HPV testing could prove useful for identifying those at highest risk of cervical precancer. Methods: Between October 1995 and August 1997, 2199 women willing to be screened for cervical cancer in peri-urban clinics in Harare, Zimbabwe received VIA, Pap smear and HPV as screening tests. The presence or absence of (pre)cancer was confirmed via colposcopy with biopsy as indicated for >97% of all women. Computerized simulations of sequential testing scenarios provided estimates of the joint (net) test qualities of different paired combinations of the three tests and allowed for comparisons with the individual test qualities. Results: Using HGSIL/CIN II-III as the reference threshold of disease, the net sensitivity and specificity of VIA and HPV when used sequentially were 63.6 and 81.9%, respectively, compared to 43.3 and 91%, respectively, when Pap smears were followed by HPV testing. VIA followed by the Pap smear yielded a net sensitivity of 37.5% and net specificity of 94.3%. Conclusions: For programs with limited resources but with the capacity for HPV testing, sequential testing involving the use of VIA followed by HPV could yield fewer false positives than the use of VIA alone at a cost of relatively few additional false negatives.