HPV Test Bests Pap Smear in Studies

WEDNESDAY, Oct. 17 (HealthDay News) -- A test to detect human papillomavirus (HPV) -- which causes most cervical cancers -- was far better than the standard Pap smear at catching malignancies, two new studies show.

What's unclear, however, is whether or not the HPV test should take the place of Pap testing, because it can have a slightly higher false positive rate, and it's not as effective in younger women.

"There are still many questions related to the use of HPV testing as the primary screening test," said Debbie Saslow, director of breast and gynecologic cancer for the American Cancer Society. "At this time, HPV testing alone (without a Pap test) is not FDA-approved as a primary screening test, so that approach is not recommended by the American Cancer Society."

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But, Saslow pointed out, "The most important message remains unchanged: Women should be screened using one of three options: a conventional Pap test, liquid Pap or Pap plus the HPV test. For women who have access to HPV testing, the HPV test offers added benefits over [Pap tests] alone."

Pap tests have been the standard screening test for cervical cancer for the past 60 years. More recently, the liquid-based or thin-smear Pap test was developed, and it was initially thought that this newer technology would offer significant advantages over the traditional Pap test. However, studies haven't conclusively found a significant benefit to the newer test. Because most cervical cancers are caused by HPV, the test to detect HPV infection is also an option for screening in addition to the Pap test.

The most recent research comparing these screening tests appears in the Oct. 18 issue of the New England Journal of Medicine. The first study, done in Canada, compares the use of conventional Pap alone to the use of the HPV test alone.

The study included more than 10,000 women between 30 and 69 years old who were randomly assigned to one of the tests. The HPV test detected 94.6 percent of the abnormal growths that can lead to cervical cancer, while the Pap test found only 55.4 percent of these growths. Women who had an abnormal result were referred for further testing. If both Pap and HPV were used together, 100 percent of the abnormal growths were found. The false-positive rate for HPV was only 2.7 percent higher than the rate for Pap smears, according to the study.