Study: Prostate Screening Saves Lives
PSA Tests Cut Metastatic Prostate Cancer by 35%
July 8, 2005 -- The PSA prostate cancer screening test saves lives, a new study shows.
For men with no symptoms of prostate trouble, PSA screening cuts the risk of deadly metastatic prostate cancer -- cancer that spreads through the body -- by 35%.
The finding comes from a study comparing 236 men with metastatic prostate cancer with 462 age-matched men without metastatic cancer. University of Toronto researcher Vivek Goel, MD, and colleagues report the findings in the August issue of The Journal of Urology.
"If this is the benefit PSA testing provides, it is going to warrant the risks involved for most men," Goel tells WebMD. "In young men with no risk factors, PSA testing may not be indicated, even at this level of benefit. For men over 50, I think it will be. And for younger men with a family history of prostate cancer or other risk factors, it will be indicated."
PSA -- prostate specific antigen -- is a chemical marker made only by cells of the walnut-sized prostate gland. The first sign of prostate cancer can be a spike in blood levels of PSA. A regular PSA test can detect early prostate cancer.
But the test is controversial. Low PSA levels don't necessarily mean a man is cancer-free. And high PSA levels don't necessarily mean a man has dangerous prostate cancer. Nevertheless, many American men get regular PSA tests -- which go hand in glove with digital rectal exams -- to screen for early prostate cancer.
Unfortunately, PSA test results remain a matter of interpretation. Doctors tend to refer men for prostate biopsy if they have a PSA score of 4 or more. But that cutoff is arbitrary -- and not particularly meaningful, says Charles A. Coltman Jr., MD, associate chairman for cancer control and prevention of the Southwest Oncology Group in San Antonio.
In this week's issue of The Journal of the American Medical Association, Coltman and colleagues reported the results of a study of some 8,600 men who underwent PSA testing. All the men in the study agreed to have a prostate biopsy -- whether or not they had a high PSA score.