Cervical cancer screening

The Pap test has been the standard screening tool for cervical cancer for years - and it still is. The test checks a sample of cervical cells under a microscope for abnormalities that may lead to cancer.

Lessons learned in the past several years are leading to changes in recommended screening frequency, and a new test is under study, according to the April issue of Mayo Clinic Women's HealthSource.

First, Pap tests don't need to be a yearly event for every woman. The American Cancer Society recommends that women over 30 who've had normal Pap results for three years can limit screening to once every two or three years. Women over age 70 who've had three normal tests in a row, no abnormal tests in 10 years and no new risk of cervical cancer (such as a new sexual partner) can opt to forgo cervical cancer screening.

Researchers are evaluating a human papillomavirus (HPV) screening as a way to detect cervical cancer earlier. Like the Pap test, the HPV test is conducted on a sample of cells collected from the cervix. The test looks for evidence of the HPV genetic material that can lead to cancer.

Two studies published in 2007 showed that the HPV test has promise. One found that the HPV test was nearly 40 percent better at identifying women with precancerous or cancerous abnormalities than the Pap test. The second study looked at using HPV and Pap screens together. This approach helped identify causes of precancerous lesions earlier than the Pap alone.

There are concerns with the HPV screen, too, including a higher percentage of false-positive results, where women who received positive HPV tests were referred for further tests that did not show any signs of cancer. HPV screening also identifies more precancerous lesions that are slow to develop into cancer or never develop into cancer.

For now, most doctors don't support HPV testing as a primary screening tool until there's more evidence to justify replacing the Pap test. Depending on a woman's age and risk factors, the HPV test may be ordered after an uncertain Pap test or, in some circumstances, may be used in conjunction with a Pap test. Women should ask their doctor which screening is best.