Can Oral Sex Cause Oral Cancer?

A public health announcement from Michael Douglas.

Actor Michael Douglas attends the 'Behind The Candelabra' Photocall during The 66th Annual Cannes Film Festival on May 21, 2013 in Cannes, France.

Actor Michael Douglas attends a Behind the Candelabra event at the Cannes Film Festival on May 21, 2013, in Cannes, France.

Photo by Andreas Rentz/Getty Images

Actor Michael Douglas has received praise in recent weeks for his portrayal of Liberace in the HBO biopic Behind the Candelabra, in part due to his somewhat graphic performances of gay sex with co-star Matt Damon. But an extremely candid interview with the Guardian over the weekend is drawing attention to Douglas’ real, heterosexual bedroom practices. Candelabra is the first film the actor has completed since receiving treatment for throat cancer two years ago, and though many assumed the disease was caused by Douglas’s well-known penchant for tobacco and alcohol, he told the Guardian it was the result of giving oral sex to female partners. Can you get cancer from cunnilingus?

Yes. You can get it from any kind of oral sex, for that matter. As Douglas suggests in the interview, a direct link has been shown between the human papillomavirus, which can be transmitted through oral sex, and oropharyngeal cancers. HPV comes in more than 100 different strains, but only a few, such as HPV-16, are among the high-risk set responsible for causing cancer. Most strains cause no symptoms, and most sexually active adults have been exposed to one or more of them. According to the Centers for Disease Control and Prevention, each year in the United States HPV causes an estimated 6,700 cases of oropharyngeal cancers in men and 1,700 in women.

So how does HPV infection, which is often symptomless, cause cancer? As the virus infects the layers of epithelial cells that coat the throat and surrounding areas, it can interrupt the cells’ normal function and cause genetic mutations. If the body’s immune system fails to identify and destroy these abnormal cells, they may continue to grow and ultimately form a cancerous tumor. The CDC notes that factors such as alcohol and tobacco use may aggravate this transformation. According the National Cancer Institute, the development from viral infection to cancer could take “between 10 and 20 years,” but “even high-grade lesions [a pre-tumor state] do not always lead to cancer.”

There is no cure for oral HPV infections, and most sexually active people will be exposed to some strain of the virus by the time they reach 26, the somewhat arbitrary age by which public health officials recommend people get vaccinated against the disease. The vaccine that has been highly recommended for the prevention of cervical cancers in women is now recommended for boys and young men as well. The CDC advised in 2011 that boys ages 11 and 12 should be vaccinated with the drug Gardasil, which is effective against HPV-16 and other strains.