Most men should not routinely get a widely used blood test to check for prostate cancer because the exam does not save lives and leads to too much unnecessary anxiety, surgery and complications, a federal task force has concluded.

The U.S. Preventive Services Task Force, which triggered a firestorm of controversy in 2009 when it raised questions about routine mammography for breast cancer, will propose downgrading its recommendations for prostate-specific antigen (PSA) for prostate cancer on Tuesday, wading into what is perhaps the most contentious and important issue in men’s health.

Task force chairwoman Virginia Moyer said the group based its draft recommendations on an exhaustive review of the latest scientific evidence, which concluded that even for younger men, the risks appeared to outweigh the benefits for those who are showing no signs of the disease.

“The harms studies showed that significant numbers of men — on the order of 20 to 30 percent — have very significant harms,” Moyer, a professor of pediatrics at Baylor College of Medicine, said in a telephone interview Thursday.

The 16-member independent panel is organized by the Department of Health and Human Services to regularly assess preventive medical care. Its recommendations have a widespread impact, especially on what services Medicare and private insurers pay for. The group’s influence was enhanced by the new federal health-care law, which will base some of its requirements for coverage on the group’s ratings.

The proposed recommendations come as doctors, researchers and policymakers are increasingly questioning whether many tests, drugs and procedures are being overused, unnecessarily driving up health-care costs and exposing patients to the risks of unneeded treatment.

Prostate cancer strikes more than 218,000 U.S. men each year. About 28,000 die of it, making it the most common cancer and second-leading cancer killer among men.

Although prostate cancer can be detected with a physical examination of the prostate, PSA testing has become the most common way that a diagnosis is made. The test measures a protein in the blood produced by prostate tissue and has significantly increased the number of prostate cancer cases being diagnosed at very early stages. But it has been a matter of intense debate whether that translates into a reduction in the death rate from the disease. Prostate cancer often grows so slowly that many men die from something else without knowing they had it.

Because it is not clear precisely what PSA level signals the presence of cancer, many men experience stressful false alarms that lead to unnecessary surgical biopsies to make a definitive diagnosis, which can be painful and in rare cases can cause serious complications.

Even when the test picks up a real cancer, doctors are uncertain what, if anything, men should do about it. Many men are simply monitored closely to see whether the tumor shows signs of growing or spreading. Others undergo surgery, radiation and hormone treatments, which often leave them incontinent, impotent and experiencing other complications.

In its last report, in 2008, the task force began to back away from PSA testing, saying that the potential harms clearly outweighed the benefits for men older than 75 and that there was insufficient evidence to recommend for or against the testing for younger men. Other groups have also increasingly been questioning the value of PSA testing.

The proposed recommendations were reported Thursday by CNN, the New York Times and the Cancer Letter, a Washington newsletter that tracks federal developments related to cancer.

As part of the task force evaluation, a team of researchers at the Oregon Health and Science University conducted an exhaustive review of the scientific literature about PSA testing, including five studies of screening and 26 studies of treatment.

“After about 10 years, PSA-based screening results in small or no reduction in prostate cancer-specific mortality and is associated with harms related to subsequent evaluation and treatments, some of which may be unnecessary,” the 116-page review concluded.

The task force plans to recommend downgrading of PSA testing to a “D” rating. The D rating means that “there is moderate or high certainty that the service has no net benefit or that the harms outweigh the benefits,” according to the task force Web site.

The task force’s new proposed recommendations drew immediate criticism from those convinced that routine screening is necessary.

The “decision of no confidence on the PSA test by the U.S. Government condemns tens of thousands of men to die this year and every year going forward if families are to believe the out-of-date evidence presented by the USPSTF,” said Skip Lockwood, chief executive of Zero, a patient-advocacy group. “A decision on how best to test and treat for prostate cancer must be made between a man and his doctor. This decision is coming from a panel that doesn’t even include a urologist or medical oncologist.”

Several other experts agreed.

“The bottom line is that we should encourage screening because it will give men the full range of options to avoid death from prostate cancer,” said William J. Catalona of the Northwestern University Feinberg School of Medicine.

J. Brantley Thrasher of the University of Kansas Medical Center said, “It appears to me that screening is accomplishing just what we would like to see: diagnose and treat the disease while it is still confined to the prostate and, as such, still curable.”

But others praised the new report, saying it would save many men from unnecessary suffering.

“Unfortunately, the best evidence is that while some men might be helped by screening, others would be harmed, and on balance the test is not useful overall,” said Howard Brody of the University of Texas Medical Branch in Galveston.

Otis Brawley, chief medical officer at the American Cancer Society, would not comment on the task force’s recommendations but said: “I have long been concerned, and it has been very apparent for some years, that some supporters of prostate cancer screening have overstated, exaggerated and, in some cases, misled men about the evidence supporting its effectiveness. We need balanced, truthful information to be made widely available to physicians and patients when making important health decisions. Sadly, that has not happened with this disease.”

Staff writer Brian Vastag contributed to this report.