Michael Douglas made headlines Sunday by pointing out there's a link between throat cancer and HPV, a virus that can be transmitted by oral sex. Since then, doctors have weighed in, saying oral sex with numerous partners is only one of several risk factors that can lead to oral cancers, including alcohol and tobacco use.
So just how risky is oral sex, anyway?
Most people know about HPV because it is the most common and preventable cause of cervical cancer, as well as genital warts. More recently, however, HPV has been linked to a dramatic rise in the incidence of mouth and throat cancers, particularly in young people. In fact, researchers estimate that about 36 per cent of oral cancers worldwide are HPV-positive.
One of the ways HPV transmission occurs is through oral sex. This transmission can happen during oral sex between men and women, or between same sex couples, male or female. And the more oral sex partners you have, the greater one's risk of exposure to a cancer-causing strain of HPV.
A 2007 study by John Hopkins University researchers published in the New England Journal of Medicine compared 100 people with oral cancers to a group of 100 people of the same age and gender who were cancer-free. "We found that sexual behaviour was a very strong risk factor for oropharyngeal cancer," said researcher Maura Gillison. "And the most strong risk factor was the number of oral sexual partners you had had over your lifetime."
Oral cancers occur most often in men. This is one of the reasons that some public health officials are advocating that boys be vaccinated against HPV, since currently only girls in Canada receive the publicly funded vaccine, Gardasil. The vaccine protects against various HPV strains, including HPV-16, which is most commonly linked to oral cancers. HPV-16 can also cause penile and anal cancers.
On Monday, a representative for Douglas said that the actor doesn't blame oral sex for his throat cancer, as was earlier reported in an interview published Monday in Britain's The Guardian newspaper (Douglas was diagnosed in 2010 and has been free of cancer for more than two years). Douglas was explaining what can cause oral and throat cancers, spokesman Allen Burry said.