HPV and cancer -- now we have numbers

The human papilloma viruses were linked to at least 25,000 cancer cases each year from 1998 to 2003, federal researchers report.

The group of 100 related viruses are most known for their connection to genital warts and cervical cancer, but they're also responsible for the common warts (papillomas) found on other parts of the body. (Here's a general fact sheet from the National Cancer Institute about the viruses.)

The new report focuses on the high-risk forms of the virus, more than 30 of which can be transmitted via sexual contact. Although most infections come and go without symptoms, some persist, raising the risk of cancer.

Using cancer data registry from 38 states plus the District of Columbia -- and creating the first big analysis of HPV-linked cases -- researchers with the federal Centers for Disease Control and Prevention reported that the top HPV-related cancer sites were the cervix, oral cavity, oropharynx (back of the throat), anus, vulva, penis and vagina.

The annual breakdown, by site:

Cervix: 10,800

Oral cavity and oropharynx: 7,400

Anal: 3,000

Vulvar: 2,300

Penile: 800

Vaginal: 600

Included in the CDC news release are some interesting gender and ethnic breakdowns. The full report, with accompanying site-specific studies, is published in the Nov. 15 supplement to the journal Cancer.

The analysis is expected to provide baseline data with which to measure the effectiveness of the somewhat controversial Gardasil vaccine. That vaccine, now recommended for girls before they become sexually active, protects against four types of the virus -- two that cause 70% of cervical cancers and two that cause 90% of genital warts.

For those unaware of HPV's effect on men, here's a CDC fact sheet on the topic. And here's information on gynecologic cancer in general.

Condoms, by the way, reduce the risk of contracting HPV sexually.

-- Tami Dennis