* Maintain Pap smear works but should happen every 3 years
* Evidence insufficient on HPV test in women over 30-panel
* Sees no difference in liquid-based vs regular Pap smear (Adds new cancer groups’ guidelines, rewrites throughout)
By Alina Selyukh
WASHINGTON, Oct 19 (Reuters) - Pap smear tests are still the best way to prevent cervical cancer, but women should not seek them every year, a U.S. government-backed expert panel and major cancer groups said on Wednesday.
Instead, every three years is a reasonable timetable, according to the U.S. Preventive Services Task Force (USPSTF), the same group that recently recommended against routine prostate cancer tests for healthy men.
Proposing changes to 2003 recommendations, the task force also said evidence is still insufficient to weigh harms and benefits of tests screening for human papillomavirus (HPV) — in contrast with the views of cancer patient advocates, who on Wednesday stepped up their support of such tests.
However, in a rare show of unity, the groups including the American Cancer Society sided with the panel on the new recommendations and proposed new screening guidelines themselves for the first time, bluntly recommending against the common practice of annual Pap tests.
In a Pap test, cells are swabbed or scraped from the cervix to be examined for cancer or precancerous changes. The same cells can be used for HPV testing to analyze for presence of viral DNA.
“If you test every year you find a lot of benign infections that would go away on their own... You end up overscreening, overmanaging and overtreating women who are not actually at risk of getting cervical cancer,” said Philip Castle of the American Society for Clinical Pathology.
The task force, comprised of primary care physicians who are experts at evidence-based research, is a highly influential in setting the tone for primary care practice.
It must weigh the potential benefits of early detection of disease through screenings against the potential harms to healthy patients who may be subjected unnecessarily to more invasive procedures or side-effects.
Echoing the panels’ recommendations, the cancer groups also said women younger than 21 do not need to get tested.
“Everybody agrees on almost everything: Let’s get rid of regular annual Pap testing, let’s get rid of teenage screenings, let’s screen women who aren’t getting screened,” said Debbie Saslow, the American Cancer Society’s director of breast and gynecologic cancer.
Side effects of overtesting could include vaginal bleeding, pain, infections, risks of pre-term delivery and psychological impacts of facing a possible cancer diagnosis, experts say.
“If you get crazy about it, you’re going to harm most of the population, and that’s the paradigm shift... Screening is not about finding disease, it’s about ruling out disease in the primary healthy population,” Castle said.
However, despite the task force’s skepticism over the effectiveness of the HPV test in preventing cancer, the cancer society and other groups called the combination of regular Pap plus HPV testing the “preferred strategy” for women over 30, if done every three to five years.
The HPV virus is very common and can cause genital warts and in some instances lead to cervical cancer, which strikes some 12,000 U.S. women every year and kills a third of them.
Usually, the immune system clears HPV on its own, especially in younger women. The task force found HPV screening causing more false positive cancer results than the Pap alone.
Cancer groups and the task force have recently come at odds over the panel’s recommendation against prostate cancer screening in healthy men. In 2009, the outcry got even more heated against the task force’s recommendation on scaling back routine mammograms in women in their 40s and 50s.
On Wednesday, the task force recommended a Pap smear test every three years for women between 21 and 65 years of age, who have had sex and have not had their cervix removed. The panel found “little to no benefit” in screening women older than 65 who had been previously tested and not enough evidence of benefit for women younger than 21.
Previously, USPSTF’s recommendations, as well as cancer groups’, told women of any age to begin testing within three years of becoming sexually active or no later than 21. (Additional reporting by Lily Kuo in Washington; Editing by Cynthia Osterman)