Accuracy of combinations of visual inspection using acetic acid or lugol iodine to detect cervical precancer: a meta-analysis

Abstract

Background: Visual inspection of the cervix with acetic acid (VIA) or with Lugol's iodine (VILI) have been evaluated for cervical cancer screening in developing countries.

Objectives: To assess the diagnostic accuracy and clinical utility of visual methods to detect cervical intraepithelial neoplasia grade 2+ (CIN2+) using: (1) VIA alone; (2) VILI alone; (3) co-testing; and (4) VILI as a triage test of a positive VIA result.

Search strategy: PubMed, EMBASE, and the Cochrane Library were searched up to May 2016.

Selection criteria: All reports on the accuracy of VIA and VILI, or combinations of VIA/VILI, to detect CIN2+ were identified. Histology and colposcopy when no biopsy was taken were used as the reference standard.

Data collection and analysis: Selected studies were scored on methodological quality, and sensitivity and specificity were computed. Clinical utility was assessed from the positive predictive value (PPV) and the complement of the negative predictive value (cNPV).

Main results: We included 23 studies comprising 101 273 women. The pooled sensitivity and specificity of VILI was 88 and 86%, respectively. VILI was more sensitive, but not less specific, compared with VIA (relative sensitivity = 1.11; 95% confidence interval, 95% CI, 1.06-1.16; relative specificity = 0.98; 95% CI 0.95-1.01). Co-testing was hardly more sensitive, but significantly less specific, than VILI alone. VILI to triage VIA-POSITIVE women was not less sensitive, but more specific, compared with VIA alone (relative sensitivity = 0.98, 95% CI 0.96-1.01; relative specificity = 1.04, 95% CI 1.02-1.05). The average PPVs were low (range 11-16%), whereas the cNPV varied between 0.3% (VILI, co-testing) and 0.6% (triage).

Conclusions: Although imperfect, VILI alone appeared to be the most useful visual screening strategy.

Tweetable abstract: VILI alone seems to be the most useful visual screening test for cervical cancer screening.

Keywords: Cervical cancer screening; VIA; VILI; developing countries; diagnostic test accuracy; meta-analysis; systematic review.