High-Resolution Anoscopy

Abstract

High-resolution anoscopy is increasingly advocated to screen HIV+ men who have sex with men for anal cancer and its precursor lesions, anal intraepithelial neoplasia. A systematic comparison between clinical features and the histopathology of suspect lesions is lacking. This study aims to analyze interobserver agreement in classifying features of intra-anal lesions suspect for anal intraepithelial neoplasia and to compare these features with their histopathological outcome. This study is a cross-sectional survey regarding high-resolution anoscopy with images and biopsies of suspect lesions. Two dermatologists experienced in high-resolution anoscopy, blinded for histopathological outcome, independently classified the lesions on clinical features. This investigation was conducted at the Dermatology outpatient clinic of the Academic Medical Center in Amsterdam, The Netherlands. Included in the study were 163 HIV+ men who have sex with men, older than 18 years, with no history of anal cancer. The primary outcomes measured were the κ-coefficient for interobserver agreement and the proportions of anal intraepithelial neoplasia per clinical feature. Three hundred four biopsies were taken from 163 patients. One hundred sixty-eight biopsies (55%) showed anal intraepithelial neoplasia, and 67/304 (22%) showed high-grade anal intraepithelial neoplasia. The κ-coefficient was 0.65 for condylomatous lesions, 0.14 for surface configuration, 0.54 for punctation, 0.08 for mosaicism, and 0.43 for atypical vessels. Condylomatous lesions showed high-grade anal intraepithelial neoplasia in 18% (95% CI, 11%-27%). In lesions with flat leukoplakia, punctation, and atypical vessels, high-grade anal intraepithelial neoplasia was seen in 25%, 30%, and 23%. In lesions with the combination punctation/atypical vessels and punctation/flat leukoplakia/atypical vessels, high-grade anal intraepithelial neoplasia was found in 38% and 40%. We did not take biopsies of healthy-looking mucosa. Furthermore, the real-time description of features during high-resolution anoscopy, instead of the use of images, would improve the recognition of subtle mucosal abnormalities. A moderate to substantial interobserver agreement was demonstrated in recognizing condylomas, punctation, and atypical vessels. Furthermore, high-grade anal intraepithelial neoplasia is present in a high proportion of intra-anal condylomata. A combination of punctation, flat leukoplakia, and atypical vessels is the best predictor for high-grade anal intraepithelial neoplasia.