MONDAY, Aug. 4 (HealthDay News) -- Updated government guidelines take a dim view of prostate cancer screenings at any age and flatly recommend against them entirely for men over 75.

The over-75 rule "is much more explicit than any recommendation out there right now" for using the prostate-screening antigen (PSA) test, said Dr. Michael L. LeFevre, a member of the U.S. Preventive Services Task Force that is updating its 2002 report.

The new recommendations are published in the Aug. 5 issue of Annals of Internal Medicine.

"The time frame is that the benefit, if there is any, from screening, is 10 years," LeFevre, a professor of family and community medicine at the University of Missouri,, added. "The average life expectancy for men over 75 years is less than 10 years, so screening them can do more harm than good."

For the same reason, men under 75 with serious health problems whose life expectancy is less than 10 years should not get, the task force report said.

Even for younger men with no health problems, "there is uncertainty about whether the benefits exceed the harm, based on existing evidence," LeFevre said.

Prostate cancer is the most common non-skin cancer in the United States, affecting one of every 6 men. Common screening tests are the PSA, which tests for protein blood levels, and a digital rectal examination, which can detect abnormal growth of the gland itself. But neither test can distinguish between prostate cancers that will become life-threatening and those that will grow so slowly that most men die with their prostate cancers, not from them.

"Most of the harms are related to treatment rather than screening," LeFevre said. Surgery and other prostate cancer treatment can cause impotence and damage urinary function and bowel function, he added.

"Men under the age of 75 should try to make an informed choice at this time," LeFevre said of screening tests. "The current evidence is not enough for us to know the balance between benefit and harm."

Current data show that a third of the men over 75 in the United States receive PSA tests, the task force report said.

A man should talk to the physician about prostate cancer screening, LeFevre said. "That discussion should occur before screening occurs and should include what the test does and does not mean, the consequences of finding cancer, and the uncertainty about whether benefit exceeds harm, based on current evidence," LeFevre said.

Medical organization make varying recommends about prostate cancer screening. The American Cancer Society position is that a test should be offered yearly to men with a life expectancy of at least 10 years, starting at age 50. Men at higher risk, such as those who have one close relative with the cancer, should begin testing at age 45, and those with several affected close relatives can have a first test at age 40, the society says.

The new guidelines "will not sit well with oncologists and a lot of people," said Dr. Susan F. Slovin, an associate attending physician who specializes in prostate cancer at Memorial Sloan-Kettering Cancer Center in New York.

"As medical oncologists, we are always trying to be one step ahead of the cancer," Slovin said. "We are trying to intervene earlier and identify patients who are at risk. We always want to intercede, to do something."

Many older men will still want prostate cancer screening, Slovin added. "These patients are very informed, and their view will be at odds with the recommendations," she said. "These are not the 75-year-olds of 50 years ago. These are physically younger people, still actively functioning sexually in many cases."

Slovin sees the screening pendulum swinging in a direction opposite to that of the new recommendation. "We are starting to make recommendations that some people be screened by the age of 35," she said.

But not everyone agrees with that assessment. Dr. Otis W. Brawley is a prostate cancer epidemiologist and chief medical officer of the American Cancer Society. He called the new guidelines, "right on target."

"The American Cancer Society since 1997 has been against mass screening," Brawley said. "But within the physician-patient relationship, a test should be offered to the patient, with the patient informed of the potential risks and potential benefits, so he can make an informed decision."

The society does not recommend against prostate cancer screening for men over 75, "but we are in the process of re-evaluating our recommendations for men of all ages," Brawley said.

In related news, the largest-ever study of its kind is shedding doubt on the prognostic value of the Gleason score, a collection of factors doctors use to gauge whether or not a patient's biopsy points to aggressive prostate cancer. The score, which ranges from 2 (least aggressive cancer) to 10 (most aggressive), is often used to decide whether men get active treatment or merely "watchful waiting."

Using biopsy and prostatectomy samples from almost 3,000 patients cared for from 1982 to 2007, researchers at the Lahey Clinic of Tufts University in Burlington, Mass., reportED that the biopsy grading system had an overall accuracy rate of only 63 percent. In fact, based on samples taken from excised prostates, 30 percent of men were found to have a higher (more aggressive) grade of cancer than their Gleason score had suggested, while 7 percent had a lower grade than the score had indicated.

The findings were published in the August issue of European Urology.

More information

Prostate cancer screening is explained by the U.S. National Cancer Institute.