HPV-Related Anal Precancerous Lesions in MSM: A Comparative Study of PrEP Users and HIV-Positive Individuals.

Abstract

Although anal cancer is rare, it disproportionately affects high-risk groups such as men who have sex with men (MSM) and people with HIV. MSM using Pre-Exposure Prophylaxis (MSM-PrEP) represent an emerging subgroup with behavioral risk factors that may increase susceptibility to high-risk human papillomavirus (HR HPV) infection and anal high-grade squamous intraepithelial lesions (HSIL). However, data on precancerous anal lesions in this group remain unexplored. To compare the prevalence and distribution of histological abnormalities detected via high-resolution anoscopy (HRA) between MSM-PrEP and MSM with HIV (HIV+MSM) and to explore the association between anal HSIL and anal swab results using cytology and HR HPV testing. This secondary exploratory analysis extended a prospective, monocentric cross-sectional study on cytology and HPV infection conducted at the HIV Reference Centre and PrEP Clinic of Universitair Ziekenhuis Brussel by incorporating histological data. A total of 85 MSM-PrEP and 93 HIV+MSM underwent HRA. Histologically confirmed anal HSIL did not differ significantly between MSM-PrEP and HIV+MSM (OR 0.6, 95% CI 0.32-1.25). No significant variation was observed in the overall histological outcome distribution (p = 0.401). A history of gonorrhea was significantly associated with HSIL (OR 2.39, 95% CI 1.03-5.55). Cytology showed limited discriminatory value, while HR HPV infection was present in all HSIL cases. Many lesions were linked to HR HPV types other than HPV16. MSM-PrEP may be at similarly high risk for anal HSIL as HIV+ MSM, underscoring the need for tailored screening strategies.