One of the leading causes of oral cancer in men could be the sexually transmitted virus that causes cervical cancer in women, according to a new study published by the Journal of Clinical Oncology.

The virus that causes cervical cancer in women, termed the HPV virus, now causes as many cancers of the upper throat as tobacco and alcohol, probably due both to an increase in oral sex and the decline in smoking, researchers say.

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

Experts say 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 US women each year. But the new study should add to the argument that there may be a direct benefit for men, too.

HPV is the leading cause of cervical cancer in women. It also can cause genital warts, 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.

To learn more about this study, contact Journal of Clinical Oncology at