WASHINGTON - Scientists advising the government have confirmed that a Pap test is a good way to screen young and middle-aged women for cervical cancer, and it is needed only once every three years. But they said there is not enough evidence yet to back testing for HPV, the virus that causes the disease.
The finding on HPV, the human papillomavirus, is at odds with guidelines issued by the American Cancer Society and other groups, which have long said that using both tests can be an option for women over 30.
Those groups and the government advisory task force separately plan to release proposed new guidelines for cervical cancer screening tomorrow and invite public comment. The task force is the same group that recommended against routine PSA tests to screen for prostate cancer, saying they were doing more harm than good for men at average risk.
Cervical cancer screening is a success story. In the United States, cases and death rates have been cut more than in half since the 1970s because of Pap smears. The test can find early signs of this slow-growing cancer and treat it before a tumor has a chance to develop.
So “the bar is set pretty high’’ for a test to replace or supplement Paps, said Dr. Evelyn Whitlock of Kaiser Permanente Northwest’s Center for Health Research in Portland, Ore.
Not enough is known about the benefits and the harms of HPV testing, according to the scientific review she led. The review was published yesterday in the Annals of Internal Medicine.
The task force that asked for the review voted unanimously in March that there was insufficient evidence to recommend for or against HPV testing, but has continued to discuss the issue and will give its advice tomorrow.
HPV infections are very common, especially in young women. They usually go away on their own and only pose a cancer risk when they last a year or more.