HPV Vaccine May Prevent Up to 61% of Anal Cancers in HIV+ US MSM
Currently available bivalent and quadrivalent human papillomavirus (HPV) vaccines could prevent up to 61.5% of anal cancers in HIV-positive men who have sex with men (MSM) in the United States, according to an HPV type analysis by the National Cancer Institute. An investigational nonavalent vaccine could prevent up to 89% of anal cancers.
New diagnoses of HPV-induced anal cancer continue to rise among HIV-positive MSM in many countries despite good responses to antiretroviral therapy. A bivalent HPV vaccine targeting HPV genotypes 16 and 18 and a quadrivalent vaccine targeting those genotypes and two others are available in the United States and elsewhere. A nonavalent vaccine targeting nine HPV genotypes is being developed.
Using cytologic and histopathologic findings, National Cancer Institute investigators determined HPV genotypes in 363.
HIV-positive MSM. They modeled the fraction of high-grade anal intraepithelial neoplasia (HGAIN) attributable to individual cancer-causing HPV genotypes and figured the range of HGAIN cases that could be prevented with HPV vaccines.
More than one quarter of men studied (26.4%) had HPV-16, the most prevalent HPV genotype. Among men with HGAIN, 55% had HPV-16.
Prevalence of two or more cancer-causing HPV genotypes rose from 30.9% in men with less than grade 1 anal intraepithelial neoplasia (AIN) to 76.3% in men with AIN grade 3 (P < 0.001 for trend).
The fraction of HGAIN cases attributable to HPV types 16 and 18 (targeted by available bivalent and quadrivalent vaccines) ranged from 12% to 61.5%. HGAIN cases attributed to HPV types 16, 18, 31, 33, 45, 52, or 58 (targeted by the investigational nonavalent vaccine) ranged from 39% to 89.4%.
The researchers believe their findings “suggest that licensed and investigational HPV prophylactic vaccines have the potential to prevent a substantial proportion of HGAIN cases in this population” of HIV-positive MSM.
The Centers for Disease Control and Prevention (CDC) recommends the bivalent or quadrivalent vaccine for gay and bisexual boys and men up 26 years old—and for those with HIV (click on link below).
Source: Vikrant V. Sahasrabuddhe, Philip E. Castle, Stephen Follansbee, Sylvia Borgonovo, Diane Tokugawa, Lauren M. Schwartz, Thomas S. Lorey, Brandon J. LaMere, Julia C. Gage, Barbara Fetterman, Sean Boyle, Mark Sadorra, Scott Dahai Tang, Teresa M. Darragh, and Nicolas Wentzensen. Human papillomavirus genotype attribution and estimation of preventable fraction of anal intraepithelial neoplasia cases among HIV-infected men who have sex with men. Journal of Infectious Diseases. 2013; 207: 392-401.
For the study abstract
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Written by Mark Mascolini on behalf of the International AIDS Society