Oral cancers like the one actor Michael Douglas referenced in a recent newspaper interview are on the rise in the United States, and doctors say that about 10,000 cases a year could be prevented with safe and effective vaccines.
The star of HBO's "Behind the Candelabra" spoke about his throat cancer that was diagnosed in 2010 and its sometime association with the ubiquitous human papillomavirus, or HPV, and oral sex.
"Because without wanting to get too specific, this particular cancer is caused by HPV [human papillomavirus], which actually comes about from cunnilingus," today's edition of The Guardian newspaper quoted the 68-year-old actor as saying.
But the actor's publicist, Allen Burry, told ABCNews.com today that his client "never said it was the cause of his particular cancer. They did discuss it. He did say oral sex is a suspected cause of certain oral cancers. He did not say it was his specifically."
About 63 percent of the estimated 11,726 cases of oropharyngeal cancers diagnosed each year in the United States are thought to be caused by HPV, according to the Centers for Disease Control and Prevention. Another 3,000 Americans are diagnosed each year with HPV-associated anal cancer and the rate of infection appears to be increasing.
"Right now in the United States only 2 percent of boys are vaccinated, which is shocking because by the time they are adults, these boys will be more likely to get cancer from HPV than girls," said Dr. Kevin Cullen, director of the University of Maryland's Marlene and Stewart Greenebaum Cancer Center.
"By the time they become adults, throat cancer from HPV in men is four times more likely than cervical cancer in women."
HPV spreads via oral, vaginal and anal intimacy, as well as through cunnilingus and fellatio. The virus does not live in the blood, semen or vaginal secretions. It takes about 20 years for exposure to the virus to develop into cancer.
Doctors say that changing sexual behaviors -- earlier sex, more partners and especially oral sex -- are contributing to a new epidemic of orpharyngeal squamous cell cancers, those of the throat, tonsils and base of the tongue.
Similarly high rates have also been seen in Europe, where a 2010 Swedish study showed a strong correlation between oral cancers and oral sex.
About 50 percent of all girls are vaccinated against HPV-related cervical cancer, a number which is slowly increasing because of strong CDC recommendations, Dr. Cullen said. Women do get HPV-related throat cancer, but at a much lower rate than men.
"The take home message is this virus is out there and virtually everyone is exposed as they become sexually active ... no matter what point in life," he said. "And boys are at greater risk than girls."
The CDC recommends two licensed vaccines, Gardasil and Cervarix, to protect against cervical, anal and oral cancers, but those guidelines have never been fully embraced by parents or young adults.
"Why not prevent what's preventable? HPV infects both sexes," Austin, Texas, pediatrician Dr. Ari Brown said. "And, while the biggest benefit for boys to get this shot is prevention against spreading it to girls, boys are at risk for other types of HPV-related cancers as well as genital warts."
But even as HPV-related head, neck and throat cancers are on the rise -- by more than 225 percent between 1988 and 2004, according to one study in the Journal of Clinical Oncology -- vaccination rates remain low.