Prophylactic HPV vaccination and anal cancer.

The incidence of anal cancer is increasing. High risk populations include HIV-positive men who have sex with men (MSM), HIV-negative MSM, HIV-positive women and heterosexual men and women with a history of cervical cancer. HPV has been detected in over 90% of anal cancers. HPV16 is the most common genotype detected in about 70% of anal cancers. The quadrivalent HPV (qHPV) vaccine has been demonstrated to prevent vaccine associated persistent anal HPV infections as well as anal intraepithelial neoplasia grades 2-3 (AIN2+) in young MSM not previously infected. A retrospective analysis also suggests that qHPV vaccination of older MSM treated for AIN2+ may significantly decrease the risk of recurrence of the AIN2+. The HPV types detected in anal cancer are included in the 9-valent vaccine. Thus, the 9-valent HPV vaccine, when administered to boys and girls prior to the onset of sexual activity, should effectively prevent anal cancer.