Michael Douglas, cancer and the growing popularity of oral sex

http://www.guardian.co.uk/film/2013/jun/03/michael-douglas-cancer-oral-sex
by Lisa Pryor

The film star's revelation highlighted the growing complexity of STDs. Should everyone avoid cunnilingus?

Michael Douglas has shared, perhaps over-shared, with readers of the Guardian, the news that oral sex caused the throat cancer he was diagnosed with three years ago. “Without wanting to get too specific,” he said, “this particular cancer is caused by HPV [human papillomavirus], which actually comes about from cunnilingus.” Could he be right?

The world of sexually transmitted infections is being turned upside down by the growing popularity of oral sex. All kinds of infections usually considered in terms of genitals are increasingly colonising the mouth. Herpes, gonorrhoea, chlamydia, and, yes, the human papillomavirus – which is implicated in cervical cancer and can cause genital warts – can be transmitted through oral sex.

Evidence of the link between HPV and oral cancer has been building for several decades. While head and neck cancers have been declining since the 1970s along with smoking rates, scientists have noticed an increase in a particular type of oral cancer. Known as “oral squamous cell carcinoma”, it is linked to the same strains of HPV known to cause cervical cancer.

Prof Andrew Grulich, who heads the HIV epidemiology and prevention program run by the Kirby Institute at the University of New South Wales, says that the majority of cancers in the back of the throat, the oropharynx in technical terms, are now caused by this virus. “Twenty years ago it was thought to be about 20% and now, depending on where you are, it seems to be 60-70%,” he says. This type of cancer is associated with having a larger number of sexual partners, and more oral sex, he says. “In terms of increased oral sex there’s solid data that an increasing proportion of people report oral sex than 20 to 30 years ago, especially for younger people.”

Older people who have oral sex are not immune. In 2010 a Taiwanese study noted the cases of two middle-aged couples, oral sex veterans with a history of more than 20 years of oral sex, where the wife was diagnosed with cervical cancer and the husband was diagnosed with oral cancer within a short period of time.

But it is not a simple case of “catching” cancer from cunnilingus. The human papilloma virus is so ubiquitous it has been found in the mouths of newborn babies. And while many sexually active adults carry the virus, very few will develop cancer.

Last year a review was published in the Journal of Sexual Medicine asking Is Oral Sex Really a Dangerous Carcinogen? Let's Take a Closer Look. Psychologist Sara E Rosenquist noted the complexity of the research, including a Finnish study of married couples which found that husbands and wives often carried different strains of the virus in their genitals and mouths, and indeed had different strains of the virus from each other, and there was no clear link with oral sex.

She concluded that: “HPV should not be a cause for concern among monogamous couples with a rich and varied sex life, as long as the sexual system remains closed and other immune compromising factors are not present. HPV becomes a concern in the context of immune system compromise and infection persistence.”

So what are oral enthusiasts to make of all this? Is it time to raid the women’s rooms of universities for all those boxes of dental dams which have been gathering dust since the 90s? Or is it time to swear off cunnilingus for good?

Nice try. The UK’s official guidelines on safer sex advice note that when it comes to spreading infections cunnilingus is less risky than fellatio, and neither is as risky as vaginal or anal sex. The guidelines admit that “while routinely advocating condom use for oral sex is unrealistic, oral sex should not be promoted as risk-free”. Ways to make oral sex safer include abstaining when you have cuts or sores on your mouth, and not brushing your teeth or flossing before oral sex.

Grulich says the good news is that cancers caused by this virus are more treatable and survivable than other oral cancers. The best news of all is that the Gardasil vaccine, which targets the virus with the aim of preventing cervical cancer, is also likely to prevent the infections which lead to these oral cancers.

As for Michael Douglas, Grulich says “good on him for going public about it and raising awareness”.