HPV: New Screening May Surpass Pap Smear
Testing for human papilloma virus "is better than the old standby Pap test at detecting cervical cancer and precancerous changes in women over 40," according to two studies published in today's Journal of the American Medical Association, the New York Times reports. While the findings are "unlikely to lead to immediate changes in medical practice in the United States," researchers said the "newer test might eventually replace the Pap test for older women or be used along with it to increase the accuracy of detection" (Grady, New York Times, 1/5). In one study, researchers examined 1,415 South African women over the age of 35, comparing "high-grade" cervical cancer detection rates for HPV tests in which women collected the samples themselves and HPV tests where clinicians had collected samples to the standard Pap smear administered by a doctor. The clinician-collected HPV test turned up an 83.9% detection rate, compared to 66.1% for the self-collected HPV test and 67.9% for the Pap smear. However, researchers also found that the Pap smear produced fewer false positives (12.3%) compared to the self-collected test (17.1%) and the clinician-collected test (15.5%) (Wright et al., JAMA release, 1/4). The second study, examining 8,554 women ages 18 and older in Costa Rica, found similar results (New York Times, 1/5). Clinician-collected HPV screenings using the Hybrid Capture II test were more sensitive than conventional Pap testing at detecting high-grade cervical disease (Schiffman et al., JAMA release, 1/4).
Hope for Poor Women
The New York Times reports that the "newer test is expected to be a great boon" in developing countries "where death rates from cervical cancer are high because Pap tests are not available." In the United States, the HPV test has been approved to help diagnose cervical cancer in women who have had abnormal Pap smears, but not for the general screening of healthy women. Dr. Thomas Wright Jr., lead author of the South African study and director of gynecologic pathology at Columbia University's College of Physicians and Surgeons, said, "I would love to see it used in women over 40 in the U.S. tomorrow. But that would require somebody going to the Food and Drug Administration and getting the test approved." Dr. Attila Lorincz, spokesperson for the test's manufacturer, said the company was considering approaching the FDA for approval. However, a "main concern is that not every woman infected with HPV will develop cancer, and the virus test is therefore more likely than the Pap test to give a false positive, which could needlessly alarm patients and lead to further testing and perhaps even unnecessary treatment if the errors were not detected." False positives are most likely among women under age 40, Wright says, noting that most women who become infected with HPV fight it off and never develop cervical cancer (New York Times, 1/5). USA Today reports that most of the approximately 80 types of HPV "are benign and cause genital warts at worst." However, "persistent infection with any one of 13 types is responsible for at least 95% of cervical cancers" (Rubin, USA Today, 1/5). Wright added that among "college-age women ... up to two-thirds have some type of HPV infection," noting that "if the virus is present in a woman over 40, it is often a sign that she has been infected for a long time and that her body has been unable to eliminate it" (New York Times, 1/5).