Oral love linked to cancer risk

US scientists have said there is strong evidence linking oral sex to cancer, and urged more studies of how human papillomaviruses (HPV) may be to blame for a rise in oral cancer among white men. In the United States, oral cancer due to HPV infection is now more common than oral cancer from tobacco use, which remains the leading cause of such cancers in the rest of the world.

Researchers have found a 225-percent increase in oral cancer cases in the United States from 1974 to 2007, mainly among white men, said Maura Gillison of Ohio State University.

"When you compare people who have an oral infection or not... the single greatest factor is the number of partners on whom the person has performed oral sex," said Gillison, who has been researching HPV and cancer for 15 years.

"When the number of partners increases, the risk increases," she told reporters at the American Association for the Advancement of Science meeting in Washington. Previous studies have suggested that people who have performed oral sex on six or more partners over a lifetime face an eight-fold higher risk of acquiring HPV-related head or neck cancer than those with fewer than six partners, she said.