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Aug. 31, 2009 -- The PSA prostate cancer screening test does more harm than good, a new study suggests.
How much harm and how much good?
"For every man who avoids a prostate cancer death due to PSA screening, about 50 men have to be treated unnecessarily -- and a third of these men will have serious problems with treatment," study co-author H. Gilbert Welch, MD, MPH, tells WebMD.
The blood test detects prostate-specific antigen (PSA) in the blood. Rising PSA levels may, or may not, mean prostate cancer. So men with suspicious PSA levels undergo prostate biopsies.
Although vast numbers of men undergo annual PSA blood tests, many professional groups, including the American Cancer Society, do not recommend routine PSA screening for prostate cancer. They instead recommend the test only for men who still want it after carefully discussing the risks and benefits with their doctor.
The PSA test became popular in 1986. What have we learned about the test's risks and benefits?
To find out, Welch, professor or medicine at Dartmouth University, and urologist Peter C. Albertsen, MD, of the University of Connecticut, analyzed data on prostate cancer collected by the National Cancer Institute and population data from the U.S. Census.
The result: From 1986 to 2005, PSA testing resulted in the diagnosis of about 1.3 million prostate cancers that would never otherwise have been detected. More than 1 million of these patients were treated with surgery or radiation.
Over that time, deaths from prostate cancer declined. Taking a conservative approach, Welch and Albertsen assumed that PSA detection of early prostate cancers -- and not improvements in treatment -- was responsible for the entire drop in prostate cancer deaths.
In that case, PSA testing would have saved about 56,500 lives. But some 943,500 men would have been "overdiagnosed."
"The overdiagnosed patient is one not destined to experience symptoms or death from the cancer," Welch says. "This means people who were never going to get a dangerous cancer get treated and suffer the ill effects of needless treatment. Overdiagnosed patients cannot benefit from treatment because there is nothing to be fixed, but they can be harmed."