Prostate cancer screening test under scrutinyby Lorna Benson, Minnesota Public Radio
St. Paul, Minn. — The value of some routine cancer screenings has been under intense scrutiny lately. A government panel recommended against routine mammograms for women under 50 last year, saying the early screenings often lead to false alarms and unneeded biopsies.
Now a growing body of evidence shows that a popular method of screening for prostate cancer may not save many lives, and could lead men to engage in unnecessary and harmful treatments.
The PSA test is one of the most widely used cancer screening tests in the United States for a cancer that is the second leading cause of death among American men. Yet several randomized studies have reported little or no survival benefit for men who get the test.
The results have divided the medical community and created a conundrum for patients who are reluctant to skip the test.
The gold standard for determining if a screening test is valuable is whether it helps improve the quality and length of a person's life. The evidence so far suggests that most men who get the PSA test will not experience either benefit.
Michael Dougherty may be one of the exceptions. He's the chairman of Dougherty Financial Group in Minneapolis. He had a PSA test at age 59, and it detected a very early stage cancer. He underwent surgery to remove his prostate.
Within a few months, the aggressive cancer was back. Twelve years later, he's still being treated for the disease.
"If somebody asks me, 'Should you be screened for PSA?' my answer is, 'That's totally up to you.' And they say, 'What would you do if you were me?' I said, 'With my personality, Type A, I'd screen myself. I'd want to know,'" Dougherty said.
It appears to take many screenings to turn up a case like Dougherty's. A large, randomized study conducted in Europe showed that 1,400 men had to be screened to save the life of just one patient.
And even then, the benefit only applied to a small sub-group of men age 55-69, and wasn't typically observed for at least 10 to 15 years.
Another randomized study out of Sweden reported a significantly better survival benefit for patients who got the PSA test. But the study population was small.
In the U.S., a similar randomized study found absolutely no survival benefit associated with the screening test.
Dr. Timothy Wilt is a general internist at the Minneapolis V.A. Medical Center. Prostate cancer is his area of research expertise.
"We've been led to believe that early detection and early treatment is necessarily beneficial," Wilt said. "There is now increasing information that that may not always be so."
There's no question that the PSA test has detected many more cancers than digital rectal exams, the other primary method of prostate cancer detection. The problem with the PSA's heightened sensitivity is that it often reveals a cancer that's not actually life-threatening.
Wilt said most PSA-detected cancers are small and slow growing, and may never need to be treated.
"The vast majority of those prostate cancers will never cause them problems in their lifetime," he said. "And the single biggest harm related to screening is the detection of prostate cancers that are unlikely to ever cause a problem in a man's life."
In the case of slow-growing prostate cancers that are not life-threatening, the treatments could be far more harmful than the actual disease.
Side effects associated with surgery and radiation on the prostate include urinary incontinence, impotence and bowel dysfunction. These side effects can be treated and often fade with time, but Wilt said anywhere from 10 to 70 percent of men still report problems with these issues two to five years later.
"That might be a price worth to pay if we knew that treatments provided substantial benefit in their length of life," he said. "It's not clear that they do."
Yet some doctors are hesitant to discourage PSA screening. Dr. Badrinath Konety is director of the Center for Prostate Cancer at the University of Minnesota.
"I would rather know, and use that information to control my life better and my decision-making better rather than not know at all, in which case I sort of don't know where I'm at," Konety said.
Konety is well aware of the results from the randomized studies. He thinks some researchers are underestimating the value of the smaller Swedish study that found benefits to PSA screening.
As an urologist, Konety said he's seen a lot of young men with aggressive cancers, whose best chance of survival depended on getting an early PSA test.
"The youngest fellow I've operated on was 31 with prostate cancer," he said. "I've seen patients in their 30s and their 40s with very aggressive cancer. I've seen them die of the disease."
The majority of men will have less aggressive cancers, and the question for them is whether they can deal with a cancer diagnosis that may not require treatment.
So far the evidence suggests that many men have not been able to resist treating their low-risk prostate cancer.
But Dr. Konety detects a growing awareness about the issue among some of his patients, and that's beginning to change their approach to treatment.
"We're making some headway," he said. "I think more and more patients come in asking for active surveillance."
Groups that develop screening guidelines have offered very little clear advice to patients on whether they should get a PSA test.
The U.S. Preventive Services Task Force, an independent group of health care experts, said men 75 and older should not get screened. But the group said there isn't enough evidence yet to assess the benefits of screening younger men.
The American Cancer Society urges men to talk with their doctor about the PSA test starting at age 50. The organization does not recommend routine PSA testing for men with average risk.
- Morning Edition, 01/18/2011, 6:25 a.m.