Wart virus makes for less deadly cancer - study

* HPV vaccine might protect against some tumors

* Patients with infections more likely to live

By Maggie Fox, Health and Science Editor

WASHINGTON, May 14 (Reuters) - A wart virus best known for causing cervical cancer may make for a less-deadly kind of head and neck cancer, researchers reported on Thursday.

People whose head and neck tumors carried the human papillomavirus virus, or HPV, were 59 percent less likely to die than people whose tumors were not caused by the virus, the researchers said.

"A patient who has this actually has a better prognosis than patients with HPV-negative tumors," Dr. Richard Schilsky, president of the American Society of Clinical Oncology and a cancer specialist at the University of Chicago, said in an interview.

He said it may be clear now that there are two kinds of head and neck cancers -- those caused by HPV and those linked to other causes, such as smoking and drinking.

Not only can patients be treated differently, perhaps waiting longer for toxic chemotherapy if they have an HPV-positive tumor, but there may be ways to prevent these tumors, Schilsky said.

Two vaccines -- Cervarix, made by GlaxoSmithKline (GSK.L) (GSK.N) and Gardasil, made by Merck & Co Inc (MRK.N) -- prevent HPV-16 infection.

"There is every reason to think that vaccination with the HPV vaccine will prevent these," Schilsky said.

Dr. Maura Gillison and colleagues at Johns Hopkins University in Baltimore studied 317 head and neck cancer patients whose tumors could be tested for HPV. The phase III study confirms earlier work Gillison's lab did linking HPV and these tumors.

They said 87 percent of patients with tumors that tested positive for HPV-16 were alive four years later, compared to 67 percent of those whose tumors did not contain the virus. All got standard treatments for their cancer.

HPV causes virtually all cases of cervical cancer, but it has been linked with other cancers including anal and penile cancer and 20 percent to 40 percent of cancers of the mouth and pharynx. It is a very common sexually transmitted disease.

Cervical cancer is the second most common cancer in women worldwide, with more than 500,000 cases diagnosed annually and 200,000 deaths.

About 400,000 cases of head and neck cancer are diagnosed globally each year, and more than half of patients die.

More details of the study will be released at ASCO's annual meeting in Orlando later this month but a summary of the findings, called an abstract, was released ahead of the meeting on Thursday.