The U.S. Centers for Disease Control says the human wart virus HPV caused 25,000 cases of cancer a year in the United States between 1998 and 2003. The CDC says that didn't mean cervical cancer, but also anal and mouth cancers.
The study suggests a broad need for screening both men and women for human papillomavirus, or HPV, another team of researchers, who did a similar survey, said.
HPV includes about 100 different viruses, and they are the leading cause of cervical cancer. The viruses, transmitted sexually and by skin-to-skin contact, can also cause anal and penile cancers, as well as cancers of the mouth and throat.
Some strains of HPV also cause common warts, although they are different from those that cause cancer.
Both Merck and Co. and GlaxoSmithKline make vaccines against some of the strains of HPV most strongly linked with cervical cancer. They are recommended for girls and young women who have not begun sexual activity.
"This gives us baseline data to measure the impact of HPV vaccine and cervical cancer screening programs in reducing the incidence of cervical cancer and other HPV-associated cancers and precancers," the CDC's Dr. Mona Saraiya, who led the study, said in a statement.
Dr. Maura Gillison of Johns Hopkins University in Baltimore, who has studied the link between HPV and oral cancers, said the findings suggest a wider use of the cervical cancer vaccines may be justified.
"Currently available HPV vaccines have the potential to reduce the rates of HPV-associated cancers, like oral and anal cancers, that are currently on the rise and for which there is no effective or widely applied screening programs," Gillison said in a statement.
HPV is the most common sexually transmitted disease in the world. About 20 million Americans currently are infected with HPV, according to the CDC.
Sometimes people clear the virus and sometimes it causes cancer. Also on Monday, a team at the University of California Los Angeles reported that HPV can make a tumor more aggressive by helping it survive, spread and resist the effects of drugs.
Writing in the journal Cancer Cell, they said the finding may lead to new and better treatments.
Last month researchers said their computer model indicated that vaccinating women as old as 45 could prevent some cases of cervical cancer, even though the vaccines do not protect anyone who has already been infected with one of the strains of HPV.
An estimated 11,070 new cases of cervical cancer will be diagnosed in 2008 in the United States, and 3,870 women will die of it.
Cervical cancer is even more widespread globally where regular Pap smear and HIV tests are not available. An estimated 500,000 women globally are diagnosed with cervical cancer each year and 300,000 die of it.
The CDC survey of 38 states and Washington, D.C., found nearly 7,400 cancers of the mouth and throat that could be linked with HPV every year -- nearly 5,700 among men and about 1,700 among women.
"There were more than 3,000 HPV-associated anal cancers per year -- about 1,900 in women and 1,100 in men," the CDC said.
