Human Papilloma Virus (HPV) Test Use Growing

Human Papilloma Virus (HPV) Test Use Growing
Test Included in Cervical Cancer Screening Guidelines

By Renee Twombly

For decades cervical cancer screening has involved an annual Pap test. Now it is becoming the standard practice for certain women also to be tested for high-risk strains of the human papilloma virus (HPV). In recent years, HPV has been found to cause 99% of cervical cancers, according to the American Cancer Society (ACS).

National recommendations to include HPV screening along with Pap testing have been made by the U.S. Preventive Services Task Force (USPSTF) and supported by the National Cancer Institute (NCI) and ACS.

Not all health care providers have adopted the new cervical cancer screening guidelines that include HPV testing, but an increasing number have, says Deborah Saslow, Ph.D., director of breast and gynecological cancers at the ACS. That includes Kaiser Permanente, the nation's largest non-profit health plan, which serves more than 700,000 women.

M. D. Anderson's Cancer Prevention Center now includes HPV testing for certain women as a part of its new cervical cancer screening guidelines, says Therese Bevers, M.D., associate professor in M. D. Anderson's Department of Clinical Cancer Prevention and medical director of the institution's Cancer Prevention Center.

Negative HPV test predicts low cancer risk

A Pap test involves using a soft swab to collect cells from a woman's cervix, the part of the womb (or uterus) that opens to the vagina. An HPV test can be carried out in the same way or by using the same Pap test sample.

While a Pap sample is studied for abnormalities in the appearance of cells lining the cervix, an HPV sample is checked for evidence that a woman is infected by one of 13 different strains of HPV, the most common sexually transmitted infection in the United States.

The difference is important, clinicians say. A Pap test finds evidence of a cancer that already is developing, whereas an HPV test can predict who is at risk for the cancer before any cellular changes occur. In the absence of HPV infection, the probability of developing cervical cancer is very unlikely. Since cervical cancer is slow-growing if both the Pap and HPV tests are negative, it is only necessary to conduct the tests every three years.

"A negative test is extremely predictive of low risk," Saslow says. "It's a great idea to use both tests every three years, and a lot of experts say that is what more women should be doing."

Cervical cancer screening and HPV

The current cervical cancer screening guidelines recommend HPV testing for some women, depending on age and risk.

Women younger than 30- It is recommended that women younger than 30 undergo a Pap test - and not an HPV test - to complete their cervical cancer screening unless the Pap test results are unclear. In that case, an HPV test will be performed to determine if a strain of the HPV virus that may lead to cervical cancer is present.

At this age, the immune system is more likely to clear the virus without treatment.

Women 30 and older- It is recommended that women who are 30 years old and older be screened for HPV during their regular Pap test. HPV testing is more effective at this age because cell changes caused by HPV infections are more persistent, leading to an increased risk of cervical cancer.

Women at increased risk of cervical cancer- Anyone having a personal history of cervical cancer, weakened immune system or diethylstilbestrol (DES) exposure before birth should talk to their health care provider about being screened annually with the Pap and HPV tests.

DES is a synthetic form of the hormone estrogen that was prescribed between about 1940 and 1971 to prevent miscarriages. DES has been linked to gynecologic cancers in daughters exposed to DES before birth.

Overcoming barriers to widespread HPV testing

Despite the trend toward use of HPV testing to predict risk of developing cervical cancer, researchers say it may take time for women to understand why this test is valuable.

At a November meeting of the American Association for Cancer Research, researchers reported that only 40% of 3,000 women polled had heard of HPV. Among that group, fewer than half were aware of the virus' connection to cervical cancer.

Additionally, some cultural barriers may have to be overcome before HPV tests become widespread, Saslow says. "Some people attach a moral judgment to the presence of sexually transmitted infections, but I believe that with increased demand and education, that stigma will diminish."

Related story:

Q&A: Cervical Cancer and HPV Testing

Resources:

Cervical cancer(M. D. Anderson)

Therese Bevers, M.D.

Cancer Prevention Center(M. D. Anderson)

What Every Woman Should Know About Cervical Cancer and the Human Papilloma Virus(American Cancer Society)

Human Papillomaviruses and Cancer: Questions and Answers
(National Cancer Institute)

U.S. Preventive Services Task Force