4 Things You Didn't Know About Oral Sex (cont.)

Researchers have found that some cancers of the oropharynx (the middle of the throat) and tonsils are probably caused by a certain type of human papillomavirus (HPV). HPV is common, but it doesn't always cause cancer. If you aren't exposed to HPV during oral sex, you're not at risk for cancer.

Brawley says that hints of a link between HPV and oropharyngeal cancer came in the late 1980s and early '90s. Researchers noticed an increase in this kind of cancer among people who hadn't been very prone to it before.

It began to affect increasing numbers of people around the age of 40 that didn't smoke or drink, whereas in prior decades these cancers were usually found in older people that smoked cigarettes and heavily drank hard liquor.  

In the early 2000s, scientists were able to use advanced DNA testing to find HPV 16 in many of these newer cancers.

Brawley determined that sexual activity must be involved.

A study published in The New England Journal of Medicine in 2007 showed a greater risk for oropharyngeal cancer in people that had had oral sex with at least six different partners. The DNA signature of HPV type 16 was often found more often in the cancers of people who had multiple oral sex partners.

It's still unclear how many people get HPV throat infections by oral sex, or how many of them get oropharyngeal cancer, Brawley reports.

Both men and women can have an HPV infection in the throat. "It doesn't discriminate by gender," Brawley says.

"The population that I thought would be least likely to get it was the first population to have this problem," he says. That population was heterosexual men aged 40-50.

Doctors know, however, that oropharyngeal cancers caused by HPV are easier to treat than those caused by factors like smoking and drinking.

Brawley says the best prevention method is still unclear, but "in terms of public awareness, this information certainly should be available to people," he says.

Expanding the use of the HPV vaccine could be one approach, but Brawley says, "I'm not sure that we have studies enough to make a blanket assertion that this is a reason to vaccinate boys for HPV." The FDA has approved the HPV vaccine Gardasil for males aged 9-26 -- but only to help prevent genital warts in those boys and young men, not as a way to curb HPV infection in their partners. The CDC's Advisory Committee on Immunization Practices allows but doesn't require boys as young as 9 to get Gardasil.

2. Oral sex enhances some adult relationships, strains others.