Sexually transmitted wart virus ups mouth cancers

WASHINGTON (Reuters) - Men should be vaccinated against a sexually transmitted wart virus to protect them against a type of mouth and throat cancer, U.S. researchers said on Monday.

They said the rate of oropharyngeal cancers -- mostly cancers of the tonsil and base of tongue -- appears to be rising in certain populations and the human papilloma virus or HPV transmitted by oral sex is likely to blame.

New vaccines that target HPV may help turn the trend around, the researchers reported in this week’s issue of the journal Cancer. The vaccines are recommended for young women in Europe and the United States.

But young men should be offered the vaccines too, said Dr. Erich Sturgis and Paul Cinciripini of the University of Texas M. D. Anderson Cancer Center in Houston.

“(We) encourage the rapid study of the efficacy and safety of these vaccines in males and, if successful, the recommendation of vaccination of young adult and adolescent males,” Sturgis and Cinciripini wrote.

There are several strains of HPV, which cause ordinary warts but also genital warts. These in turn can cause cancer in some cases. The researchers looked at various studies and concluded that HPV 16 was especially likely to be linked with certain cancers of the tonsil and base of tongue.

Smoking is a well known risk factor but rates of these cancer are staying fairly steady, despite declines in tobacco use.

In one study cited by Sturgis and Cinciripini, Dr. Maura Gillison of Johns Hopkins University in Baltimore and colleagues studied 100 patients with oral or throat cancer and compared them to 200 healthy people. They found those who had six or more oral sex partners had a high risk of the cancer.

They found evidence of HPV-16 in 72 percent of the tumors.

U.S. health officials estimate that more than a quarter of U.S. girls and women aged 14 to 59 are infected with HPV.

Two vaccines protect people against HPV infection -- Merck and Co’s. Gardasil and GlaxoSmithKline’s Cervarix. The U.S. Centers for Disease Control and Prevention has recommended vaccination for 30 million women and girls aged 11 to 26 to prevent cervical cancer, which kills about 300,000 women worldwide each year.

Head and neck cancers, which include cancers of the larynx, nose and nasal passages, mouth, pharynx, and salivary glands, are three times more common in men than women, and 45,000 new cases are expected in 2007 in the United States alone.