Researchers at the Johns Hopkins Kimmel Cancer Center say that a virus transmitted via oral sex – human papillomavirus (HPV) – is one of the highest risk factors in contracting certain types of throat cancer.
The scientists say that they have conclusive evidence that HPV causes some throat cancers in both men and women. Reporting in the May 10 issue of the New England Journal of Medicine, the researchers found that oral HPV infection is the strongest risk factor for the disease, regardless of tobacco and alcohol use, and having multiple oral sex partners tops the list of sex practices that boost the risk for the HPV-linked cancer.
The study’s author and cancer virus expert Maura Gillison, M.D., Ph.D., first reported the connection between HPV and specific throat cancers in 2000, supporting previous work by other investigators. “We believed the links were strong, but needed to understand which behaviors put people at higher risk,” says Gillison.
In Gillison’s study of 100 men and women newly diagnosed with oropharyngeal cancer, those who had evidence of prior HPV infection – usually transmitted via oral sex – were 32 times more likely to develop the cancer. This was much higher than the rate increase of threefold for smokers and 2 Â½ -fold for drinkers.
Study participants who reported having more than six oral sex partners in their lifetime were 8.6 times more likely to develop the HPV-linked cancer. In a surprising twist, Gillison says their data show no added risk for HPV carriers who smoke and drink alcohol. “It’s the virus that drives the cancer,” explains Gillison, an assistant professor of oncology and epidemiology at Johns Hopkins. “Since HPV has already disrupted the cell enough to steer its change to cancer, then tobacco and alcohol use may have no further impact.”
Oral sex, including both fellatio and cunnilingus, is the main mode of transit for oral HPV infection, the investigators say, although mouth-to-mouth transmission remains possible and was not ruled out by the current study.
Gillison added that “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.” She also said that it is possible that consistent condom use may reduce risk.