Evaluation of visual inspection with acetic acid (VIA), Lugol's iodine (VILI), cervical cytology and HPV testing as cervical screening tools in Latin America. This report refers to partial results from the LAMS (Latin AMerican Screening) study

Abstract

Objectives: To assess the performance indicators of visual inspection with acetic acid (VIA) and visual inspection with Lugol's iodine (VILI) in four Latin American centres participating in the ongoing Latin AMerican Screening (LAMS) study, in settings with moderate incidence of cervical disease and with poorly to moderately well-organized cervical cancer screening.

Setting: Three Brazilian centres (São Paulo, Campinas and Porto Alegre) and one Argentine centre (Buenos Aires) recruited a total of 11,834 healthy women to undergo VIA, VILI, conventional Pap smear and Hybrid Capture II (HCII).

Methods: Women who had a positive result from any of these tests were subjected to colposcopy and biopsies (if necessary), and women with high-grade cervical intraepithelial neoplasia (CIN) were properly treated. To control for verification bias, 5% of women with normal tests were referred for colposcopy, as were 20% of HCII-negative women.

Results: Data on VIA (n=11,834), VILI (n=2994), conventional Pap smear (n=10,138) and HCII (n=4195) were available for test comparisons, calculating sensitivity, specificity, and positive and negative predictive values. Overall test positivity was 11.6% for VIA, 23.0% for VILI, 2.2% for Pap smear (LSIL threshold), 1.1% for Pap smear (HSIL threshold) and 17.1% for HCII. VIA was positive in 61.8% of the women with CIN 1, 57.0% of those with CIN 2, 35.0% of women with CIN 3 and in 21 of 28 (75%) of women with cancer. Approximately 10% of women with no detectable disease had an abnormal VIA. Regarding VILI, 83.3% of women diagnosed with CIN 1 and 62.5% of those with CIN 3 had an abnormal test. VILI failed to detect one of three cases of cancer. Both the sensitivity, specificity and positive predictive value of VIA and VILI in detecting CIN 2 or CIN 3 could be significantly improved depending on the combination with Pap smear or HCII (sensitivity up to 100.0% and specificity up to 99.8%).

Conclusions: The LAMS study failed to reproduce the performance figures obtained with VIA and VILI (as stand-alone tests) in some other settings, where the prevalence of cervical disease was higher. However, a combined use of VIA or VILI with the Pap test or HCII allowed specific detection of cervical abnormalities.