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. Instead, every three years is a reasonable timetable, according to the 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. 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. Echoing the panels' recommendations, the cancer groups also said women younger than 21 do not need to get tested. 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.