Prostate Test: No Survival Benefit?
Men Who Died Had PSA Cancer Screening Test as Often as Those Who Lived
Jan. 9, 2006 -- Does PSA screening for prostate cancer reduce risk of death? New research suggests the answer is no, but the truth may not be known for several years, one expert says.
A study from the Yale School of Medicine and the VA Connecticut Healthcare System found no evidence that PSA screening improved survival in men with prostate cancer.
Researchers concluded that men should not be told that annual PSA screening can reduce their risk of dying from the cancer.
"Unfortunately, screening tests can sometimes find cancer, even at early stages, but not prolong survival," says researcher John Concato, MD, MPH.
"Rather than encouraging annual screening of all men starting at age 50, as is commonly done, the limited effectiveness of PSA testing should be explained to patients in the process of obtaining their informed consent to the test."
Test's Value Unclear
More than 230,000 American men were diagnosed with prostate cancer in 2005, and while one in six men will have prostate cancer in a lifetime, one in 34 will die from it, according to figures from the American Cancer Society.
Prostate specific antigen, or PSA, is a chemical marker made only by cells of the prostate gland. The blood test for PSA is widely used but poorly understood for the screening of prostate cancer.
The problem? Low PSA levels don't necessarily mean a man doesn't have the disease, and high levels don't necessarily mean that prostate cancer will progress and become life-threatening.
The American Cancer Society urges doctors to offer PSA screening and digital rectal exams to men beginning at age 50. Men at high risk, including black men, should begin testing at age 45, according to the ACS.
But the group does not recommend routine testing, and it calls on doctors to inform their patients about the "benefits and risks of testing at annual checkups."
The ACS guidelines on PSA testing state that patients "should actively participate in the decision by learning about prostate cancer and the pros and cons of early detection and treatment of prostate cancer."
Likewise, the U.S. Preventive Services Task Force says the evidence isn't strong enough to recommend routine PSA testing, and the American College of Physicians also calls on its members to explain the pros and cons of the test to their patients.
The ambiguity stems from the fact that the research on the value of PSA in prostate cancer has been mixed.
In a study reported last July, researchers in Canada found that screening reduced the risk of developing advanced disease by 35%.
The latest study, published today in the Archives of Internal Medicine, followed a similar design but used long-term survival as its endpoint.