DENVER (The New York Times News Service) -- A sexually-transmitted virus that causes cervical cancer has been linked to cancers of the tonsil and tongue in men -- diseases that have been on the rise in men for the last 30 years, according to a study by a Colorado Springs doctor and researcher.

Since 1980, such throat cancers have increased of 11 percent nationally.

"Nobody knows that this is going on, and it's important to understand the risk," said Joel Ernster, a professor at the University of Colorado Denver School of Medicine and principal author of the study, which appeared in the journal Laryngoscope.

The trends point to oral sex as a likely mode of transmission and have prompted some to call for boys to be vaccinated against the human papilloma virus, Ernster said.

Girls can already receive a vaccine to prevent cervical cancer.

"Based on what they know right now, why the hell aren't they giving it to boys?" asked Jon Helander, 56, and a patient of Ernster's in Colorado Springs.

Helander went through radiation and chemotherapy to fight a virus-related tongue cancer earlier this year and said he's frustrated that his son, 21, can't be vaccinated against the virus, as his daughter, 23, has been.

Ernster said he was trying to understand the shift he was seeing among throat cancer patients shift away from older, long-time smokers and drinkers to 45- to 55-year-old men married for 15 to 20 years.

"But if you ask what they did before that, they were promiscuous, had a lot of different encounters and oral sex was part of their lives," Ernster said.

Helander, whose cancer tested positive for the human papilloma virus, said his history fits the pattern. "Let's see -- 20, 30 years takes me back to my years in the military," Ernster said.

"So, yes, I know where it came from." Helander's ex-wife was not infected.

Cancers related to the human papilloma virus have a long latency, showing up 20 or more years after infection, said Aimee Kreimer, an National Institutes of Health epidemiologist who has published research linking human papilloma virus to some throat cancers.

The sexual revolution of the '60s has contributed to the rise of viral-associated oral cancers, Kreimer said.

It's not yet clear why women aren't getting more of the cancers, she said.

Kreimer and Ernster said they are worried that people are still underestimating the risks of oral sex, but both also said the human papilloma virus vaccine could eventually cut cancer rates.

Gardasil, manufactured by Merck & Co., can prevent HPV infection in girls, preventing cervical cancer.

"We're optimistic it will protect from infection at other anatomical sites, too," Kreimer said.

Merck spokeswoman Jennifer Allen said the company does not yet have plans to test the vaccine in boys or men. "It's all still new," Allen said.

Copyright 2008 The New York Times News Service. All rights reserved.