The new advice is the latest pushback from routine screening to hunt for early cancers. Last year, a government task force said most women don't need mammograms in their 40s and a doctors group said most women in their 20s don't need annual Pap tests.
American men have long been urged to have prostate cancer screenings, but over time studies have suggested that most cancers found are so slow-growing that most men could have avoided treatment.
The Atlanta-based cancer society is perhaps the most influential group in giving screening advice. Its new guidance released Wednesday on prostate cancer urges doctors to:
--Discuss the pros and cons of testing with their patients, including giving them written information or videos that discuss the likelihood of false test results and the side effects of treatment.
--Stop giving the rectal exam as a standard prostate cancer screening because it has not clearly shown a benefit, though it can remain an option.
--Use past PSA readings to determine how often followup tests are needed and to guide conversations about treatment.
Prostate cancer is the most common non-skin cancer in American men. An estimated 192,000 new cases and 27,000 deaths from it occurred last year in the United States.
But it is a slow-growing cancer in many cases, and depending on a man's age, he may be more likely to die of something else. Major studies have suggested routine screening doesn't save lives and often leads to worry and unnecessary treatment.
The new cancer society recommendations could be "game changers" in two respects, said Dr. John Davis, a urologist who directs prostate cancer screening programs for the University of Texas M.D. Anderson Cancer Center in Houston.
First, they could change how routine physical exams for many older men are conducted, he said. About 41 percent of men 50 and older get annual prostate cancer screenings. Even though the cancer society doesn't recommend routine PSA tests, many doctors do it without even asking their patients. And there's little conversation about it unless the test gives a worrisome result. The new guidelines may spur doctors to talk to their patients earlier about the pros and cons of getting the test in the first place.
Second, the guidelines could have a chilling effect on community prostate screening clinics in which hundreds of men line up and get free, quick exams, Davis said.
That was the intent, said Dr. Andrew Wolf, a University of Virginia physician who led the group that write the new guidelines.
"Yes, the guideline was explicitly crafted to put a damper on those community prostate screening activities that do not offer men the opportunity to make an informed decision whether to screen," Wolf said.
Prostate cancer screening became a medical mantra in the 1990s, thanks to the development of the PSA test. Some celebrities became advocates for routine testing, including former New York City Mayor Rudy Giuliani and the actor Brad Garrett from the TV sitcom "Everybody Loves Raymond." In 2008, Garrett underwent an on-the-air digital rectal exam for a TV special called "Stand Up To Cancer."
But concerns about the value of routine screening increased last year, after two large studies concluded screening for prostate cancer doesn't necessarily save lives, and noted any benefits can come at a high price.
The American Urological Association -- a longtime proponent of regular screening -- last year backed off its call for annual tests after age 50. The group said men should be offered a baseline PSA test at age 40, with follow-ups at intervals based on each man's situation.
The group also has stood by the rectal exam as a standard part of screening, saying it can find cancer that the blood test does not.
The cancer society has been more cautious about regular screenings for some time. The organization last issued guidelines in 2001, which said merely that doctors should offer screening and discuss the risks and benefits.
The new guidelines back away even more, dropping the sentence that doctors should offer prostate screening. Instead, the society says some evidence indicates periodic screening can save lives but that there are significant uncertainties about the overall value of finding prostate cancer early. Screening should not take place, the new advice says, unless a patient is fully informed of the trade-offs.
In a nod to the busy workload of doctors, the guidelines recommend videos, brochures and other "patient decision aids."
Men at average risk should get detailed information around age 50, the society recommends. Men at higher risk, including African-Americans and men with a father or brother who had prostate cancer before age 65, should get the information beginning at age 45. Men with more than one close relative with prostate cancer before 65 should get such information at age 40.
For men who want to be screened regularly, the new guidelines recommend every other year if the PSA reading is less than 2.5, a measure of prostate specific antigen per milligram of blood. Annual tests are recommended for 2.5 or higher and a 4 suggests consideration of a biopsy.
The urological association considers the cancer society's advice too simplistic and says it's important to consider any rapid rise in PSA results.
The society's new guidelines rankled Skip Lockwood, president and CEO of Zero -- The Project to End Prostate Cancer, formerly known as the National Prostate Cancer Coalition.
Lockwood's group recommends annual PSA tests for men beginning at 45, and conducts mobile prostate cancer screening programs at state fairs, churches and other sites. The group provides information about the risks and benefits of screening, and connects men to follow-up care if needed, he said.
What bothers him most in the new guidance is "the certainty of its tone," Lockwood said.
"We acknowledge that the PSA test is lacking. I think nobody disagrees on that fact. I think that we all understand that this is not cut and dry -- not an all or nothing situation," he said.