Anal cancer precursors common among older San Francisco MSM, study says

Anal high-grade squamous intraepithelial lesions (HSIL), a precursor of anal cancer, are common among older men who have sex with men (MSM), whether or not they are living with HIV, according to a recent study—leading to the authors’ recommendation that all older MSM should be screened for anal cancer.

About This Study

“Prevalence of anal HPV infection and anal HSIL among MSM 50 years and older living with or without HIV” was published online on May 2, 2024, in Journal of Acquired Immune Deficiency Syndromes. The lead author is Alexandra L. Hernandez, Ph.D., M.P.H., of the Department of Medicine at the University of California in San Francisco.

Key Research Findings

The study, which enrolled participants from 2018 to 2022, investigated the frequency of anal human papillomavirus (HPV) infection and resulting anal high-grade squamous intraepithelial lesions in MSM who are ≥ 50 years old. Participants included 129 men living with HIV and 109 HIV-negative men living in the San Francisco, California, area. They were tested for anal HPV and underwent a high-resolution anoscopy. Visible lesions were biopsied.

Most participants were white and the majority were < 60 years old (54% of participants were 50-59 years, while 10% of participants ≥ 70 years old). HIV-negative participants were more often employed full time, had higher household incomes, and had a higher educational level than participants living with HIV. Among participants living with HIV, 94% had an undetectable viral load and 33% had CD4 cell counts < 500 cells/mm³.

Fewer participants living with HIV had HPV-16, the most common oncogenic papillomavirus type, than HIV-negative participants (19% and 22%, respectively, for the two groups). Other cancer-causing papillomavirus types, as well as lesions, were more common in the HIV group than in the HIV-negative group (51% vs. 34% for HPV and 47% vs. 37% for lesions). Lesions were strongly associated with oncogenic papillomavirus types independent of HIV status, with 18%-20% of all participants having papillomavirus types that are not covered by current HPV vaccines.

Discussion Highlights and Implications for Practice

Study limitations reported included the cross-sectional nature of the design, a small convenience sample, and the San Francisco study site characteristics.

Given the high prevalence of lesions in both groups, study authors recommended that MSM who are 50 years or older be screened for anal cancer independent of HIV status. Prevention messaging also needs to be adapted to this older age group, they said.

Further research is needed into the potential for including additional HPV types in new HPV vaccines, the researchers suggested.

By Barbara Jungwirth