High-Grade AIN Among HIV-Infected Men Who Have Sex with Men

In a 3-year prospective study, the cumulative incidence of high-grade anal intraepithelial neoplasia was 37% among HIV-infected MSM receiving ART.

The incidence of anal cancer has been increasing since the introduction of potent combination antiretroviral therapy (ART), but the reasons are unclear. In the present study, researchers evaluated the incidence of high-grade anal intraepithelial neoplasia (AIN) among 247 HIV-infected men who have sex with men (MSM) who were either initiating or already receiving potent ART. Participants underwent anal cytological analysis and high-resolution anoscopy (HRA) at baseline and then every 6 months to 1 year for 3 years.

During follow-up, 17% of participants had high-grade squamous intraepithelial lesions at least once, and 54% of participants had high-grade AIN (AIN2/3) at least once. In two men (1% overall), the condition progressed to invasive anal cancer. At 3 years, the cumulative incidence of high-grade AIN was 37%, and the progression rate from a lesser abnormality at baseline was 12.8 new cases per 1000 person-months. In a multivariate analysis, several factors were significantly associated with high-grade AIN: age 40, CD4 count <50 cells/mm³ before ART initiation, and infection with human papillomavirus (HPV) type 16 or 18. Treatment with the same ART regimen for at least 4 years was associated with a reduced risk for high-grade AIN.

Comment: Although this study was small, it furthers our understanding of the risk for progression of AIN among HIV-infected MSM in the current treatment era. The incidence of new high-grade AIN may have been overestimated if lesions were missed on initial screening. Nevertheless, the data support the need for aggressive screening for AIN in the routine care of individuals who have engaged in receptive anal sex — and the aggressive monitoring of AIN when it is discovered. Although ART may provide some benefit in terms of reducing the risk for progression of AIN, the effect is not overwhelming. What we do not yet know is whether early detection and treatment of AIN in the ART era confers a reduction in the incidence of invasive cancer or improves survival.

— Sonia Nagy Chimienti, MD

Published in Journal Watch HIV/AIDS Clinical Care March 28, 2011