"Testing women for human papillomavirus HPV may catch more precancerous growths than standard cervical cancer screening does  but more evidence is needed before the newer tests become routine a study published Monday concludes.  The report in the Annals of Internal Medicine sums up a research review done for the U.S. Preventive Services Task Force USPSTF an expert medical panel supported by the federal government.  The USPSTF is set to update its recommendations on cervical cancer screening which were last laid out in .  At that time the task force recommended that sexually active women get regular Pap tests to screen for cervical cancer. But it said there was not enough evidence to recommend for or against newer types of testing  including HPV tests and the liquidbased Pap tests that are now more often used than the oldfashioned version.  During Pap tests cells are swabbed or scraped from the cervix for examination under a microscope to find cancer or possible precancerous changes. In the socalled liquidbased version the cells are placed in special preservative liquid designed to make the specimen easier to read those same cells can also be used for HPV testing unlike the cells collected with conventional Pap tests.  Exactly what impact the new research review will have on the USPSTF recommendations is anyones guess. A draft of the guidelines will not be published until Wednesday when it will be available for public comment on the task force website here .usa.govxXexl http.usa.govxXexl.  A lot of research has been done since the  recommendations said Dr. Evelyn P. Whitlock a senior investigator with Kaiser Permanente Northwest in Portland Oregon who led the review.  But there are still questions about the effects of HPV screening and more complete evidence is needed before it becomes widely used Whitlock and her colleagues write.  HPV is a common virus that causes warts including genital warts. Usually the immune system clears the infection but persistent infection with certain strains of HPV leads to cervical cancer in some women.  So in recent years tests for those highrisk HPV strains have been developed to help in screening for the disease. A few HPV tests are approved for use along with Pap tests for screening women age  or older. The tests are not approved for younger women because they give doctors little information younger women commonly have HPV infections that go away on their own.  It has not been clear exactly how HPV testing or liquidbased Pap tests measure up against standard Pap tests.  In their review Whitlocks team examined four clinical trials including more than  women that compared older Pap tests with the liquidbased version.  They found that both tests had nearly the same sensitivity  which refers to their ability to detect cancer or precancer. The tests also had the same specificity which can be used to measure how often a screening test produces falsepositive results.  Across studies the falsepositive rate ranged between about six percent and  percent for both conventional and liquidbased Pap tests.  Its reassuring to know that they perform equivalently Whitlock told Reuters Health.  In an interview she noted that the decision of whether to do a conventional or liquidbased Pap test is not the patients. It may not even be the doctors  but may instead depend on whatever health system he or she is part of.  Several other clinical trials in the review looked at HPV testing. In general Whitlocks team found HPV tests were more sensitive than conventional Pap tests but they were less specific meaning they had a higher falsepositive rate.  In a  trial of more than  women for example HPV testing caught  percent of potentially precancerous growths versus  percent with Pap tests. But the falsepositive rate was  percent compared with two percent with Pap testing.  The problem with that higher falsepositive rate is that it could lead to needless biopsies and other tests or treatment to remove abnormallooking tissue.  Its a tricky thing to get your mind around Whitlock said. It may seem that if a test is more sensitive it must be better. But its more subtle than that. Youre trying to make a tradeoff between sensitivity and specificity.  Since cervical cancer screening is repeated over time whats needed is evidence of the longerterm effects of different tests according to Whitlock. How often for example does HPV testing lead to biopsies versus Pap testing  And no one knows yet whether HPV testing actually catches cervical cancer at an earlier stage or reduces deaths from the disease compared with Pap tests.  Clinical trials are ongoing Whitlock said. The state of the science will be changing relatively quickly so well have to keep looking at this.  Right now the American Cancer Society ACS and other medical groups recommend that women start Pap tests at age  or three years after they become sexually active whichever comes first. Those should be done every one to two years until age  after age  women whove had three normal Pap tests in a row can be screened less often  every two to three years.  Pap plus HPV testing done every three years is considered a reasonable option for women age  and up according to the ACS.  Whitlock called Pap testing one of the big public health success stories.  Nationally the cervical cancer death rate dropped by  percent between  and  and routine Pap testing is credited for most of that decline.  But many women still do not get regular Pap screening Whitlock pointed out. Its thought that more than half of cervical cancer cases in the U.S. occur in women whove never been screened or havent been in the past five years.  If more women received the screening that already exists that would be a huge step forward Whitlock said.  An estimated  U.S. women will be diagnosed with cervical cancer this year and nearly  will die from the disease according to the ACS.  SOURCE bit.lyatTzv httpbit.lyatTzv Annals of Internal Medicine online October  . Our StandardsThe Thomson Reuters Trust Principles. httpthomsonreuters.comenaboutustrustprinciples.html Sponsored"