The sexually transmitted virus that brings about cervical cancer in women is now proving scary for men, too.
According to new research, the HPV virus now causes as many cancers of the upper throat as tobacco and alcohol, courtesy both an increase in oral sex and a decline in smoking.
The only available vaccine against HPV, and manufactured by Merck & Co. Inc., is currently given only to girls and young women. But Merck plans this year to seek government permission to offer the shot to boys.
Experts vouch that a justification for male vaccinations would be to prevent men from spreading the virus and to help reduce the nearly 12,000 cases of cervical cancer diagnosed in U.S. women each year. Still, the new study should add to the argument that there may be a direct benefit for men, too.
"We need to start having a discussion about those cancers other than cervical cancer that may be affected in a positive way by the vaccine," says study co-author Dr. Maura Gillison of Johns Hopkins University.
The study is documented in the Journal of Clinical Oncology.
Human papillomavirus, or HPV, is touted as the leading cause of cervical cancer in women. It also can cause genital warts, penile and anal cancer .
Previous research by Gillison and others gives HPV as a primary cause of the estimated 5,600 cancers that occur each year in the tonsils, lower tongue and upper throat. It is an acknowledged fact that the virus' role in such cancers has been rising.
The current study examined more than 30 years of National Cancer Institute data on oral cancers. Researchers classified about 46,000 cases, using a formula to divide them into those caused by HPV and those not connected to the virus.
Researchers say that the incidence rates for HPV-related oral cancers have risen steadily in men from 1973 to 2004, becoming about as common as those from tobacco and alcohol.
"If current trends continue, within the next 10 years there may be more oral cancers in the United States caused by HPV than tobacco or alcohol," says Gillison .
Research gives that oral sex is associated with HPV-related oral cancers, though a cause-effect relationship has not been proved. Other researchers have suggested that even unwashed hands can spread it to the mouth.
Gillison points toward sex as an explanation for the increase in male upper throat cancers. Still, HPV-related upper throat cancers have dipped significantly in women from 1973 to 2004.
Merck's vaccine, approved for girls in 2006, comes as a three-dose series priced at about $360. It is designed to protect against four types of HPV, including one associated with oral cancer.
Merck has been testing the vaccine in an international study, but it is focused on anal and penile cancer and genital warts, not oral cancers, says Kelley Dougherty, a Merck spokeswoman.
"We are continuing to consider additional areas of study that focus on both female and male HPV diseases and cancers," she adds.