ATLANTA -- Actor Michael Douglas' comments about throat cancer have thrown a spotlight on cancer risks from a sexually spread virus.
The virus, HPV, is best known for causing cervical cancer. But experts say it also is a growing cause of certain types of oral cancer, those in the upper throat -- specifically at the base of the tongue and in the tonsils. Studies suggest that HPV can be blamed for 60 percent to 80 percent of those cancers.
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In the U.S., the American Cancer Society estimates there will be nearly 14,000 new cases of upper throat cancer this year.
Researchers say women sometimes get oral cancer caused by HPV, but the risk is greatest and rising among men. A small study in Baltimore found men accounted for about 85 percent of recent HPV-related oral cancers, said Dr. Sara Pai, a Johns Hopkins University researcher.
Men seem to have lower amounts of antibody protection against HPV, said Pai, who advised that men and women abstain from oral sex if their partner has an active HPV infection.
"It's important to know your partner and to know their history of sexually transmitted diseases, so you understand your full risk when you become intimate," she said.
As many as 75 percent of sexually active men and women will be infected with HPV at some point. But most clear the infection on their own within two years. Some, however, have difficulty ridding themselves of HPV. And in some cases, the virus creeps down through tiny fissures in the base of the tongue or in the tonsils to lodge deep in the tissue. Those deep-settling infections can become dangerous cancers that often aren't diagnosed until they're at a late stage, Pai said.
The connection between HPV and oral sex has been known. But it was cancer survivor Douglas' interview with the Guardian, a British newspaper, that grabbed headlines on the subject. Douglas noted that oral sex and the virus HPV can be one cause of oral cancer.
Douglas also has been a smoker and drinker. Tobacco especially has been identified as the cause of most other cancers in the head and neck, including in the voice box and at the front of the tongue.
But tobacco-related cancers have been waning, while oral cancers tied to HPV have been rising.
Symptoms of throat cancer can include a sore throat that doesn't go away, pain or trouble swallowing, a lump in the back of the throat, ear pain and voice changes.