HPV

HPV and Cervical Cancer from WebMd

Nearly two decades ago, experts discovered a relationship between infection with HPV (human papillomavirus) and cervical cancer. Since then, these experts have learned much more about how HPV can lead to cervical cancer.

Here, what every woman and girl should know about HPV and cervical cancer.

About the HPV Virus

There are more than 100 types of HPV. About 30 or so types can cause genital infections. Some can cause genital warts; other types can cause cervical or other genital cancers. (The other 70 or so HPV types can cause infections and warts elsewhere on the body, such as on the hands.)

Most sexually active women and men will contract HPV at some point in their lifetime. Most will never even know it. Usually, this virus does not cause any symptoms and doesn't cause disease. Often, the body can clear HPV infection on its own within two years or less.

Some types of HPV, typically HPV 6 and HPV 11, cause genital warts. The warts are rarely associated with cervical cancers. They are considered "low-risk" HPV.

HPV and Cervical Cancer

Certain HPV types are classified as "high-risk" because they lead to abnormal cell changes and can cause genital cancers: cervical cancer as well as cancer of the vulva, anus, and penis. In fact, researchers say that virtually all cervical cancers -- more than 99% -- are caused by these high-risk HPV viruses. The most common of the high-risk strains of HPV are types 16 and 18, which cause about 70% of all cervical cancers.

If the body clears the infection, the cervical cells return to normal. But if the body doesn't clear the infection, the cells in the cervix can continue to change abnormally. This can lead to precancerous changes or cervical cancer.

Rates of Cervical Cancer

Actual cervical cancer is rare in the U.S. because most women get Pap tests and have abnormal cells removed before they turn into cancer. The American Cancer Society predicts that about 11,070 women will find out they have cervical cancer in the U.S. this year. They also say that roughly 3,870 women will die of the disease the same year.

How HPV Is Spread

HPV types associated with genital infections are transmitted sexually, primarily through skin-to-skin contact during sexual activity. HPV can also be spread through oral sex. The chance of getting HPV rises with certain risk factors:

• Number of lifetime sexual partners (risk increases with more partners)
• Young age: Women aged 20 to 24 are most likely to be infected, but they usually clear the HPV infection with no problems.
• Women who are sexually active with men who have other partners at the same time.

Symptoms of High-Risk HPV Infection and Tests

When infection with high-risk HPV types occurs, there usually are no symptoms. Often, the first clue is a Pap test result that is abnormal. In a Pap test, the doctor takes a swab of cervical cells and has them analyzed in a laboratory. If the Pap test results are unclear, the doctor may order a HPV test to check the DNA type of the virus. This analysis can identify 13 of the high-risk HPV types associated with cervical cancer. It does not identify cancer. But it tells the woman and her doctor if she has a type of HPV capable of causing cancer.

Treatment of HPV Infection

A positive HPV test may not mean a woman needs treatment, at least not immediately. Having a positive test puts a woman in the "high-risk" class, alerting the doctor that she is at higher risk for cervical tissue changes and may need close evaluation.

To watch for further tissue changes, the doctor may order frequent Pap tests. Or the doctor may perform a colposcopy, in which a lighted magnifying device is used to closely examine cervical tissues.

Researchers have discovered that high-risk HPV viruses produce certain proteins. These proteins interfere with the cell functions that limit excessive cell growth.

If abnormal cervical tissue changes progress, treatment of the HPV infection may be needed. Among the options are surgery, laser treatment, and freezing.

Pregnant women, or women considering pregnancy, should consult closely with their doctor. The risk of passing HPV on to the baby is very low. But HPV treatments can affect pregnancy, so doctors may want to delay treatment until after childbirth.

How to Prevent HPV Infection

There's only one sure way to eliminate any chance of HPV infection: Avoid all genital contact with another person. To reduce risk, it's best to have a mutually monogamous sexual relationship with an uninfected partner. But keep in mind, many people don't know if they're infected. Using condoms can help prevent HPV transmission but are not foolproof. The virus can be transmitted to genital areas not covered by the condom.

A vaccine, Gardasil, was approved in 2006 for use in girls and women aged 9 to 26. It is also approved for use in females and males (also aged 9 to 26) to prevent genital warts and anal cancer.

Another vaccine, Cervarix, may be approved by the FDA in 2007. Over time, widespread vaccination will help prevent transmission of the HPV types covered by the vaccines.

The Gardasil HPV vaccine protects against several high-risk strains of HPV, including HPV types 16 and 18, which account for 70% of cervical cancers. It also protects against HPV 6 and 11, which account for about 90% of genital warts. Cervarix, if approved, would protect against HPV types 16, 81, 31, and 45 -- all of which can cause cervical cancer.