By Brett Spiegel
Though prostate cancer risk can be detected using blood tests that measure prostate-specific antigen (PSA) -- a protein discharged by the prostate gland -- care should be taken to minimize potential dangers associated with PSA testing, according to a review of prostate cancer screening studies in the Annals of Internal Medicine.
Prostate cancer is the most common form of cancer in men. Since many men are unaware that they have developed or may be at risk for prostate cancer -- which can grow extremely slowly and possibly be fatal -- physicians emphasize screening. But screening strategies are fallible.
Current prostate cancer screening protocol has been controversial, mainly due to confusion on the part of doctors and patients about how to proceed if a PSA test result indicates possible cancer. Additionally, doctors often recommend rectal needle biopsy in response to elevated PSA levels, but these biopsies have side effects (infection, heavy bleeding, pain) and don't necessarily give an accurate assessment of the severity of prostate cancer.
The U.S. Preventive Services Task Force (USPSTF) recommends not using PSA tests.
"If we look at numbers and play that out, on the positive side, screening 1,000 men will at most avoid one prostate cancer death from screening. Between 100 to 120 will have a false-positive result -- an elevated PSA, but no prostate cancer -- and the result is a lot of unnecessary biopsies," says Michael L. LeFevre, MD, MSPH, co-vice chair of the USPSTF. "The benefit doesn't outweigh the harm. Therefore we don't recommend the test."
"Many men will have prostate cancer detected and treated even though it's a cancer that would not cause them any harm," adds Dr. LeFevre.
The researchers who wrote the Annals report evaluated 35 screening models for prostate cancer -- comparing the rate of lives that may have been theoretically saved due to PSA screening to the number of unnecessarily performed biopsies due to varying PSA levels, age, and sporadic testing. They found that stricter guidelines regarding biopsy referrals and less frequent testing of men with consistently low PSA levels, could balance the rate of over-diagnosis.
Better understanding of when and why PSA tests are effective at screening for prostate cancer would make PSA testing a more viable option, the researchers wrote. The ultimate goal is to "screen smarter, not harder," according to the report.
"A PSA screen is not dangerous. It's not harmful. It's what you do with that information," said Tom Kirk, President and CEO of UsTOO International Prostate Cancer Education and Support Network. "A PSA is an imperfect tool, but it's the best one we have right now."
"What needs to follow is an open and honest discussion between what the science tells us of the benefits and harms of screening," LeFevre says. "If a man chooses to be screened, it should be an informed choice."
"More Evidence That PSA Testing May Do More Harm Than Good" originally appeared on Everyday Health.