All age groups of sexually active, human immunodeficiency virus (HIV)-negative men who have sex with men have a high prevalence of anal cancer precursors, which may reflect their ongoing sexual exposure to human papillomavirus (HPV), and which may explain high rates of anal cancer, according to a new study.

HPV infection can cause anal and cervical cancers and their associated precancerous lesions. Knowledge of the age-related prevalence and natural history of cervical cancer precursors in women has guided the development of cervical cancer screening strategies for women. Similar information could help develop anal cancer screening strategies, particularly for men who have sex with men, a population in which anal cancer rates are high.

To determine the age-related prevalence of and risk factors for anal cancer precursors in men who have sex with men, Peter V. Chin-Hong, M.D., of the University of California, San Francisco, and colleagues obtained anal cytology and behavioral data from 1,262 HIV-negative men ages 18 to 89 in four U.S. cities: Boston, Denver, New York, and San Francisco.

The prevalence of low-grade and high-grade precancerous lesions was 15% and 5%, respectively, and did not change with age. This risk of low-grade lesions was associated with having more than five male anal sex partners, any use of "poppers" (alkyl nitrites used as recreational drugs) within the previous 6 months, use of injection drugs two or more times a month during the previous 6 months, older age at first anal intercourse, and infection with a greater number of HPV types. The risk of high-grade lesions was associated with any anal HPV infection and infection with an increasing number of HPV types.

Contact: Peter V. Chin-Hong, University of California, San Francisco, 415-502-9585, pvch@itsa.ucsf.edu

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Contact: Sarah Zielinski
jncimedia@oupjournals.org
301-841-1287
Journal of the National Cancer Institute
14-Jun-2005