High Rates of Human Papillomavirus Infection Found in Men | NCI Cancer Bulletin for March 8, 2011 - National Cancer Institute

High Rates of Human Papillomavirus Infection Found in Men

A study of the incidence of genital human papillomavirus (HPV) infections in men has found that half of the participants were infected with at least one type of the virus, including types that can cause genital warts and cancer. The incidence of infection was both high and relatively constant across age groups (from 18 to 70 years of age), Dr. Anna Giuliano of the H. Lee Moffitt Cancer Center and Research Institute and her colleagues reported in a study published online February 28 in The Lancet.

Approximately 40 HPV types can be transmitted sexually. Some of these HPV types cause genital warts, and others (so-called high-risk or oncogenic types) can cause cancer. In men, HPV-related cancers include cancers of the penis, oral cavity, oropharynx (a subset of the head and neck that includes the tonsils), and anal canal.

Two vaccines that prevent persistent infections with the two high-risk types of HPV responsible for 70 percent of cervical cancers have been approved by the FDA for use in young women for the prevention of cervical cancer and some vulvar and vaginal cancers. One of these vaccines, Gardasil, also protects against infection with the two HPV types that cause 90 percent of genital warts and has been approved for use in young men and women for prevention of genital warts. And last December, Gardasil was approved for use in young men and women for the prevention of anal cancer. The new findings about the natural history of HPV infections in men provide much-needed information for developing realistic cost-effectiveness models about the use of HPV vaccinations in males internationally, the researchers said.

The cohort study enrolled 1,159 men from Brazil, Mexico, and the United States to investigate the prevalence and clearance of HPV in men. The acquisition of new infections was strongly associated with sexual behavior, as was the likelihood of clearing an infection. The median duration of infection with any HPV type was about 7 months, and for HPV 16, an oncogenic type, it was about 12 months. By the end of the 3-year study period, the majority of men had cleared their HPV infection.

In women, the risk of HPV infection is known to decline with increasing age. But this study found that in men, by contrast, the risk of infection appears to be stable throughout their lives. “If indeed men remain at high risk of acquiring new HPV infections throughout their lives, then vaccination of older men might be warranted,” the researchers said.

Because of strict criteria used for enrollment, the estimates of HPV incidence cannot be generalized to all men in the three countries, the researchers noted. They also cautioned against drawing conclusions about infection rates in other populations based on these results, although they noted that all studies to date have found high acquisition rates of HPV infection in men.

For more see: Human Papillomaviruses and Cancer: Human Papillomaviruses and Cancer - National Cancer Institute


Human Papillomaviruses and Cancer


Key Points
- Human papillomaviruses (HPVs) are a group of more than 150 related viruses, of which more than 40 types can be sexually transmitted. Some sexually transmitted HPVs cause genital warts, whereas others, called high-risk or oncogenic HPVs, can cause cancer (see Question 1).
- Genital HPV infections are very common, but most occur without any symptoms and go away without any treatment over the course of a few years (see Questions 1, 4, and 5).
- Sometimes, HPV infections can persist for many years. Persistent infections with high-risk HPVs are the primary cause of cervical cancer. HPV infections also cause some cancers of the anus, vulva, vagina, penis, and oropharynx (see Question 3).
- The U.S. Food and Drug Administration has approved two vaccines, Gardasil® and Cervarix®, that are highly effective in preventing infection with the two HPV types that cause most cervical cancers. Gardasil also prevents infection with the two HPV types that cause most genital warts (see Question 6).

NCI Cancer Bulletin for March 8, 2011 - National Cancer Institute