TORONTO -- Genital warts and human papillomavirus-related cancers in men are costly and emotionally burdensome conditions that should be prevented with HPV vaccination, according to Susan Rosenthal, Ph.D.
"Vaccinating males also represents a more equitable public health policy in that it recognizes that both genders contribute to the transmission of HPV," Dr. Rosenthal said at the annual meeting of the Society for Adolescent Health and Medicine (SAHM).
The Food and Drug Administration approved the quadrivalent HPV vaccine (Gardasil) for boys aged 9-26 years in October 2009. Since then, the Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices has given a permissive recommendation for vaccination for boys at the discretion of the physician, a recommendation that is supported by a SAHM position paper, said Dr. Rosenthal, whose research has focused on adolescent sexual health and vaccine acceptability.
Although 13 HPV types cause cervical cancer--a well-known bit of information--Dr. Rosenthal pointed out that in a 2006 study, HPV-16 was determined to cause several other cancers, including vulvar, vaginal, anal, penile, and oropharyngeal cancers. There is some evidence also linking HPV-16 to laryngeal and nonmelanoma skin cancer, said Dr. Rosenthal, a pediatric psychologist at Columbia University Medical Center and Morgan Stanley Children's Hospital of New York-Presbyterian.
"So we know that HPV causes cancer in men," said Dr. Rosenthal. Indeed, based on 2008 estimates of the annual number of new cases of HPV-related cancers in U.S. men, of the 38,260 cases involving the oral cavity and oropharynx, larynx, anus, and penis, 10,969 (28.6%) were attributed to HPV infection, according to data from the American Cancer Society and other sources.
In a recent study (New England Journal of Medicine, in press, 2010), the HPV vaccine was found to be 90% effective in preventing external genital lesions, a category that included external genital warts, penile/perianal/perineal intraepithelial neoplasia, and penile/perianal/perineal cancers. Of the 1,397 men and women who received the vaccine, there were only three cases of external genital lesions, all three of which were condyloma.
"It's not fun to have these diseases or the work-up for these diseases. If we use a female-only strategy, we will not protect men who have sex with men, and we don't know at [age] 11 who are the men who have sex with men. And this is a prophylactic vaccine," said Dr. Rosenthal.
In the discussion following Dr. Rosenthal's presentation, some controversy erupted over whether all boys should receive the HPV vaccine or only boys who are likely to have sex with other males should be vaccinated.
"Historically, at least in this country, we're terrible at gender-based vaccination, we don't have high uptake when we try to do risk-based strategies. Vaccinating men will also be the fastest way to achieve protection for women, and vaccinating males is an arguably more equitable public health policy because it recognizes that both genders contribute to the transmission of HPV," argued Dr. Rosenthal.
Audience member Dr. Gary Remafedi of the University of Minnesota Amplatz Children's Hospital, Minneapolis, countered: "There is observational data indicating the benefits of immunizing young men who have sex with men, but we're still awaiting comparable data for the general male population. As we await that data, I believe it would be a disservice not to immunize young men who have sex with men as soon as they are identified as at least being likely to have sex with men. It is absolutely the job of the physician to identify these people."
"I can't predict sexual behavior in the young male.... I think a lot of 11-, and 12-, and 13-year-olds, which is the age at which I think we should immunize, are not clear in their own minds whether they want to have sex with other men," responded Dr. Rosenthal.
Some of the reasons for not vaccinating males, she said, include the questionable cost effectiveness, particularly if high rates of female vaccinations are achieved, and the issues of overall costs.
In separate interviews, Dr. Carol A. Ford and Dr. Marianne E. Felice both felt comfortable with the recommendation to vaccinate both boys and girls against HPV.
"When you look at cost-effectiveness analyses, it is important to figure out whether you are including negative outcomes for men and women, or just for men. STDs affect both partners, so it's an interesting discussion whether you look at the burden of the sexually transmitted disease for both men and women or if you try to isolate it to one partner or the other," said Dr. Ford, director of the adolescent medicine program at the University of North Carolina at Chapel Hill and director of the N.C. Multisite Adolescent Research Consortium for Health.