Anal Cancer Screening in Men Who Have Sex With Men in the Multicenter AIDS Cohort Study.

Objective: To evaluate the prevalence of anal cytology (ACyt) abnormalities among HIV-infected and HIV-uninfected men who have sex with men (MSM).

Design: Multicenter cohort study of 723 HIV-infected and 788 HIV-uninfected MSM with ACyt, with a second ACyt collected 2 years later. A referral for high-resolution anoscopy was suggested for abnormal ACyt.

Methods: ACyt samples were collected using a polyester swab and liquid cytology media and read in a central laboratory.

Results: Prevalence of any abnormal ACyt was 25% in HIV-uninfected MSM and increased to 38%, 41%, and 47% among HIV-infected MSM with current CD4 T-cell counts ≥500, 350-499, and <350 cells/mm (P < 0.001), respectively. Anal HPV16 DNA was also more common in HIV-infected than HIV-uninfected MSM (25% versus 16%, P < 0.001). Abnormal baseline ACyt together with prevalent HPV16 DNA detection was present in only 7% of HIV-uninfected MSM compared to 18% of HIV-infected MSM with current CD4 < 350, P < 0.001. Among HIV-infected men, 56% of the men with atypical squamous cells of undetermined significance or low-grade squamous intraepithelial lesions ASCs-US/LSILs and 81% of men with atypical squamous cells cannot exclude high-grade (ASC-H/)/high-grade squamous intraepithelial lesions (HSIL) had lower grade ACyt findings 18-30 months later ("regressed"). However, 19% of untreated HIV-infected men with ASC-H/HSIL cytology maintained that same grade of cytology in their second test approximately 2 years later, and 15% with ASC-US/LSIL "progressed" to ASC-H/HSIL. Abnormal ACyt had high sensitivity (96%) but low specificity (17%) for biopsy-proven HSIL.

Conclusions: Prevalence of abnormal ACyt remains elevated in HIV-infected men during the current antiretroviral therapy era.