Although widespread Prostate-Specific-Antigen (PSA) testing has undoubtedly decreased prostate cancer mortality, is there a point of diminishing returns?
In a study published in the April 2009 issue of The Journal of Urology, researchers found that in a subgroup of elderly men, among those who were 75 years old or older and had a PSA below 3 ng/ml (nanograms per milliliter), none subsequently died of prostate cancer. The discontinuation of routine PSA screening in these men may not increase the rates of undetected lethal disease, and could avoid potentially unnecessary treatments and reduce diagnostic costs.
Because PSA screening can find cancers that may become life-threatening in 5 to 25 years, there has been increased usage of the test in 40 to 50-year-olds. But the test can also discover cancers that never become life-threatening, perhaps in up to 30% of the cases. Many men who are older than 75 undergo continued PSA screening, potentially leading to unnecessary treatment since death from other causes is more likely than death from prostate cancer.
The study conducted by investigators from the Baltimore Longitudinal Study of Aging (National Institute on Aging, National Institutes of Health) and the Department of Urology at Johns Hopkins School of Medicine involved 849 men (122 with and 727 without prostate cancer) with serial PSA measurements . Researchers found that for men over 75 with PSA < 3ng/ml, none died of prostate cancer and only one developed high-risk prostate cancer. In contrast, men of all ages with a PSA ?3.0 ng/ml had a continually rising probability of death from prostate cancer.
Writing in the article, Edward M. Schaeffer states, “The optimal approach to prostate cancer screening remains controversial. To date, there is limited evidence from which to inform the decision on when to discontinue prostate cancer screening. Our findings suggest that men at an age of 75-80 years who have a PSA level below 3ng/ml are unlikely to be diagnosed with a high risk prostate cancer during life. These men may therefore represent an ideal target group for discontinuation of PSA testing, which could dramatically reduce the costs associated with screening and the potential morbidity of additional evaluations and/or treatment in a population unlikely to gain benefit.” Dr. Schaeffer emphasized that these findings need to be confirmed in a much larger study, and that men over the age of 75 years should continue to be monitored for development of clinical signs of prostate cancer.
The article is “Prostate Specific Antigen Testing Among the Elderly: When To Stop?” by Edward M. Schaeffer MD, PhD, H. Ballentine Carter MD, Anna Kettermann MA, Stacy Loeb MD, Luigi Ferrucci MD, PhD, Patricia Landis BS, Bruce J. Trock PhD, and E. Jeffrey Metter MD. It appears in The Journal of Urology, Volume 181, Issue 4 (April 2009) published by Elsevier.