NEW YORK - A relatively new screening test was about twice as accurate as the traditional Pap smear at spotting cervical cancer, according to the first rigorous study of the test in North America.
The new test could replace the 50-year-old Pap technique in a matter of years, researchers say. And there's a bonus for women: They won't need a screening as often.
The HPV test, which looks for the virus that causes cervical cancer, correctly spotted 95 percent of the cancers. The Pap test, which checks for abnormal cells under a microscope, found only 55 percent, according to researchers at McGill University in Montreal, who published their findings in today's New England Journal of Medicine.
"We've had the Pap test for over 50 years and it's high time it be replaced by technology that's more robust," said Eduardo Franco, director of McGill's division of cancer epidemiology, who led the study.
Franco said some doctors worried the HPV test would result in more false alarms, causing anxiety and requiring more follow-up testing. In the study, there were only slightly more false positives for the HPV tests (6 percent) than the Pap smears (3 percent).
HPV, or human papilloma virus, is a common sexually transmitted disease. Infections are mostly in young women and most go away on their own. The HPV test looks for the high-risk viruses that can cause cervical cancer if the infection persists. Like the Pap, it uses cells scraped from the cervix, the lower part of the uterus.
Because the Pap test misses about half of the cases, doctors use frequent testing to catch the slow-developing cancer at its earliest, most treatable stages.
The HPV test has been available in the United States since 2000 and was first used as a follow-up to inconclusive Pap tests. Now women over 30 can get the HPV test - but only along with a Pap - and, if both tests are negative, wait three years to be tested again.
Scientists have been studying whether the HPV test can be used alone and whether it can prolong the intervals between exams. Debbie Saslow, director of breast and gynecologic cancer for the American Cancer Society, said evidence from a number of studies supports using the HPV test in place of a Pap.
"Overall, I don't think there's any doubt that HPV testing has a lot of advantages over the Pap test," she said.
Saslow said there are still issues to be resolved, and federal approval needed, but "it's definitely coming." She said clinicians expect that to happen sometime in the next decade.
The government-funded Canadian study included 10,154 women ages 30 to 69. The women got both tests.