The human papilloma virus (HPV) vaccine prevents anal cancer in young men, a new study says.
Vaccinated men and boys in the study had a 75 percent reduced risk of anal cancer . Participants in the study were men who have sex with men – a group at particularly high risk for the disease.
"Almost six thousand people every year in this country are diagnosed with anal cancer, and more than 700 people die from the disease," said study researcher Dr. Joel Palefsky, director of the Anal Neoplasia Clinic at the University of California, San Francisco. "What this trial showed is that those cancers and deaths could be prevented."
The HPV vaccine was originally intended to prevent cervical cancer in girls and women. Yesterday, an advisory panel for the Centers of Disease Control and Prevention (CDC) voted to recommend the vaccine for boys as well . The new study was one piece of evidence the CDC considered before making its recommendation.
The study will be published tomorrow (Oct. 27) in the New England Journal of Medicine.
HPV and cancer
Anal cancer can be caused by infection with HPV. The HPV vaccine Gardasil protects against infection with HPV 16 and 18, the most common HPV types involved in anal cancer, and HPV 6 and 11, the most common types in genital warts.
The new study included 602 men who have sex with men between the ages of 16 and 26 from Australia, Brazil, Canada, Croatia, Germany, Spain and the United States. All of the participants had had at least one, but no more than five, sexual encounters over the study period.
Participants were randomly assigned to receive the three shots of the Gardasil vaccine, or a placebo. Researchers followed up with the patients for three years after their last shot.
Effective for boys and men
The vaccine reduced anal infections with HPV, and lesions that can lead to cancer known as high-grade anal intraepithelial neoplasia.
The vaccine reduced the incidence of these cancer precursors by nearly 75 percent among those who had not been previously exposed to any of the HPV types in the vaccine. Among those who had been previously exposed to one or more of the virus strains in the vaccine, the vaccine reduced the incidence of the precancerous lesions by 54 percent.
"The ideal time to begin vaccination would be before initiation of sexual activity, but vaccination may also be useful after initiation of sexual activity," Palefsky said.
Pass it on: The HPV vaccine reduces the risk of anal cancer in men who have sex with men.