HPV gains as source of oral cancer in men, study finds

ATLANTA — The sexually transmitted virus that causes cervical cancer in women is poised to become one of the leading causes of oral cancer in men, according to a new study.

The human papillomavirus (HPV) now causes as many cancers of the upper throat as tobacco and alcohol, probably due to an increase in oral sex and the decline in smoking, researchers said.

The only available vaccine against HPV, made by Merck, is given only to girls and young women. But Merck plans this year to ask government permission to offer the shot to boys.

Experts said a primary reason for male vaccinations would be to prevent men from spreading the virus and help reduce the nearly 12,000 cases of cervical cancer diagnosed in U.S. women each year. But 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," said study co-author Dr. Maura Gillison of Johns Hopkins University.

The study was published Friday in the Journal of Clinical Oncology.

HPV is the leading cause of cervical cancer in women. It also can cause genital warts, and penile and anal cancer, risks for males that generally don't get the same attention as cervical cancer.

Previous research by Gillison and others established HPV as a primary cause of the estimated 5,600 cancers that occur each year in the tonsils, lower tongue and upper throat.

The new study looked at more than 30 years of National Cancer Institute data on oral cancers. Researchers categorized about 46,000 cases, using a formula to divide them into those caused by HPV and those not connected to the virus.

They concluded the incidence rates for HPV-related oral cancers rose steadily in men from 1973 to 2004, becoming about as common as those from tobacco and alcohol.

The good news is that survival rates for the cancer are also increasing. That's because tumors caused by HPV respond better to chemotherapy and radiation, Gillison said.

Studies suggest oral sex is associated with HPV-related oral cancers, but a cause-effect relationship has not been proved.

Merck's vaccine, approved for girls in 2006, is a three-dose series priced at about $360. It is designed to protect against four types of HPV, including one associated with oral cancer.

Government officials and the American Cancer Society said they don't know whether Merck's vaccine will be successful at preventing disease in men. The company is testing that in an international study.

Indeed, it's not clear that the vaccine even prevents the HPV infection in males, let alone cancer or any other illness, said Debbie Saslow of the American Cancer Society.