Almost 620,000 gay and bisexual men in the United States were living with HIV in 2014, and 100,000 of these men were not even aware of their infection.
These men are 100 times more likely to have anal cancer than HIV-negative men who exclusively have sex with women. Yet, no national screening guidelines exist for anal cancer prevention in any population.
Anal cancer is predominantly caused by chronic or persistent human papillomavirus (HPV) infection.
HPV infection can lead to the development of anal precancer which, if remains undetected or not adequately treated, may lead to anal cancer.
Likewise, HPV infection is also responsible for causing cervical, vaginal, vulvar, oropharyngeal, penile and rectal cancers.
The objective of screening is to identify and treat these precancers to prevent the occurrence of anal cancer.
However, one of the reasons for the lack of screening guidelines is that anal precancer treatment has not yet been shown to prevent invasive cancer.
Our study, published today in the journal Cancer, attempts to find a possible solution to prevent anal cancer in HIV-positive gay and bisexual men, using the best available data.
We found that age-specific anal precancer management, including post-treatment HPV vaccination, can potentially lead to an 80 percent decrease in lifetime risk of anal cancer and anal cancer mortality among gay and bisexual men.
Anal cancer: the next big crisis
Some in the medical community have identified anal cancer as the next big crisis among HIV-infected gay and bisexual men. Initiation of antiretroviral therapy in the 1990s greatly reduced the AIDS-related death rate and improved survival.
However, this improvement in survival led to an increase in the lifetime risk of developing anal cancer, especially among HIV-positive gay and bisexual men.
Anal cancer is typically preceded by persistent HPV infection that often leads to precancer.
HPV is common among U.S. men; about one out of two men in the general population has HPV infection. HPV typically clears naturally; however, under certain circumstances, it might persist longer and might progress to anal precancer. If it remains undetected, untreated or inadequately treated, this precancer can progress to anal cancer.