Stop PSA Screening in Men Over 75 — But Only Those With Low PSA, Says New Study

Zosia Chustecka

February 20, 2009 — New data that support discontinuing screening for prostate cancer in men older than 75 years are reported in the April issue of The Journal of Urology.
However, the new analysis does not suggest that screening be stopped in all men older than 75 years, but only in men who have low levels of prostate-specific antigen (PSA ≤3 ng/mL).
This group is unlikely to develop aggressive prostate cancer or to die of this disease during their remaining life and, therefore, these men may represent an ideal target group for discontinuation of PSA testing," say the researchers, headed by Edward Schaeffer, MD, PhD, from the Department of Urology at Johns Hopkins University School of Medicine, in Baltimore, Maryland.
Not screening these older men would dramatically cut costs and would eliminate harm from additional evaluations and/or treatment in a population unlikely to experience benefit, they add.
The conclusions tie in with, but differ from, the recent recommendation from the US Preventive Services Task Force (USPSTF), which advised stopping screening in all men who are 75 years or older, as reported by Medscape Oncology
All men older than 75 years of age may not be equal.
However, as Dr. Schaeffer and colleagues point out, "all men older than 75 years of age may not be equal."
"Indeed, in our cohort, no patient older than 75 years with a PSA of less than 3 ng/mL had high-risk prostate cancer," they write. "However, of those with a PSA greater than 3 ng/mL, there were several subsequent prostate cancer deaths."
The findings come from a new analysis of data collected in the Baltimore Longitudinal Study of Aging, in which investigators collected serial PSA measurements in 849 men, of whom 122 developed prostate cancer.
Questions About the Use of a PSA Cut-Off Level
However, 2 editorial comments that accompany the new study question the conclusion about stopping screening only in older men with low PSA levels.
The implication is that it may not be safe to discontinue testing if PSA is above this level," says Peter Albertsen, MD, from the University of Connecticut Health Center, in Farmington.
But there are still many questions about whether PSA testing identifies clinically significant disease and about how effective treatment is in older patients, he writes. For example, a recent update of the Scandinavian Prostate Cancer Group-4 trial showed no benefit associated with radical prostatectomy for men older than 65 years (J Natl Cancer Inst. 2008;100:1144).
"While we may be able to prevent a few deaths from prostate cancer in patients older than 75 years, this comes at an enormous cost in testing and treatment," Dr. Albertsen comments.
The USPSTF made similar points about men who are 75 years and older. For these men, and others who have a life expectancy of 10 or fewer years, the incremental benefit from treating prostate cancer detected by screening is "small to none." Therefore, harm outweighs benefit, it concludes (Ann Intern Med. 2008;149:185-191).
In another editorial comment, Ruth Etzioni, PhD from the Fred Hutchinson Cancer Research Center, in Seattle, Washington, points out that the conclusions are based on observational data. In particular, the selection of the 3 ng/mL PSA cut-off level is based on a post hoc observation. "Post hoc findings may be valid but generally need to be confirmed in independent datasets," she writes.
The researchers have disclosed no relevant financial relationships.