Oral sex has been linked to throat cancer in a new study by the New England Journal of Medicine .

Human papillomavirus (HPV), which can be transmitted during oral sex, is the main cause of oropharyngeal (throat) cancer, researchers found. The study is the first to prove the link.

Researchers compared 100 men and women who were recently diagnosed with oral cancer with 200 similar people without the disease.

They found that participants who reported having oral sex -- fellatio or cunnilingus -- with six or more partners were at the highest risk (8.6 times more) of develping throat cancer.

"It's the human papillomavirus that drives the cancer," Dr. Maura Gillison, the lead author of the study, told The Globe and Mail .

Gillison, an assistant professor of oncology and epidemiology at Johns Hopkins University in Baltimore, Md., said the more oral-sex partners an individual has, the greater the risk is of getting oral cancer.

Researchers found that those with HPV infection were 32 times more likely to develop oropharyngeal cancer -- regardless of the previously established risk factors of tobacco and alcohol use.

While there is no screening test for the cancer, Gillison said the risk is relatively low.

"People should be reassured that oropharyngeal cancer is relatively uncommon, and the overwhelming majority of people with an oral HPV infection probably will not get throat cancer," said Gillison.

There is also a new vaccine -- Gardasil -- that protects against several strains of HPV, including the one linked to oral cancer. However, it has not been specifically tested in relation to oral cancer.

The Tories have set aside $300-million for an HPV vaccination program for girls aged nine to 11 but debate remains about the long-term effectiveness and morality of the plan.

According to the Canadian Cancer Society, 3,200 Canadians will get oral cancer in 2007 and 1,100 will die from the disease.