HPV vaccination to prevent anal cancer in men who have sex with men

Prevention of cancer remains a challenge in many areas of medicine. The discovery of the association of human papillomavirus (HPV) to anogenital cancers has led to the successful development of preventative vaccines. Men who have sex with men (MSM) are disproportionately affected by HPV-related cancer, particularly anal cancer, where rates are over 15 times higher than in heterosexual men (OR 17.3; 95% CI 8.2 to 36.1).1 This is driven by disease in HIV-positive MSM in whom the very high rates of anal cancer are increasing despite highly active antiretroviral treatment (HAART). The incidence of anal cancer during the HAART period (post-1996) was estimated to be 131 cases per 100 000 person years (py), corresponding to a demographically adjusted rate ratio of 80.3.2 This compares with cervical cancer rates of 15.0 and 9.8 per 100 000 py before and after the introduction of the cervical screening programme.3 There are only a few studies of anal cancer in HIV-negative MSM, but rates also appear to be increased. In the Multicenter AIDS cohort study (MACS) the incidence of confirmed anal squamous cell carcinomas was 5 (95% CI 1 to 18) per 100 000 py.4 Oncogenic HPV types are estimated to cause 80% or more of anal cancers.5 The UK has vaccinated girls for HPV through school programmes since 2008. Initially using the bivalent vaccine Cervarix, it moved to the quadrivalent HPV (qHPV) vaccine Gardasil in September 2012. Like many other countries, the UK decided to vaccinate girls only, on the basis of the likely herd immunity benefit that will accrue to boys. Data from Australia support this hypothesis. A dramatic decline in anogenital …