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Prostate Cancer Among Men with PSA 4.0 ng/mL

In prostate cancer screening, further evaluation frequently is advised when serum prostate-specific antigen (PSA) levels exceed 4.0 ng/mL. However, this threshold will miss cancers associated with PSA levels lower than 4.0 ng/mL.

To determine the prevalence of prostate cancer in patients with low PSA levels, researchers analyzed data from the placebo group of a previously published prostate cancer prevention trial (Journal Watch Jul 18 2003). After 7 years of observation, 2950 men (age range, 62-91) with normal digital rectal examinations and PSA levels consistently 4.0 ng/mL underwent prostate biopsies in which at least six samples were taken. The overall prevalence of prostate cancer among these men was 15%; it ranged from 7% among men with PSA levels 0.5 ng/mL to 27% among those with PSA levels of 3.1-4.0 ng/mL. Sixty-seven men (15% of those with prostate cancer; 2.3% of the entire cohort) had high-grade prostate cancers (Gleason score, 7-9).

Comment: These findings confirm that prostate cancer is not always associated with elevated PSA levels. But the implications for practice are unclear: We don't yet have a noninvasive way to predict which tumors are destined to become symptomatic, nor do we have any definitive evidence that screening reduces mortality. An editorialist -- who appears to support PSA screening generally -- nevertheless concludes that we should not lower the PSA threshold for recommending biopsy in men who are older than 50.

— Allan S. Brett, MD

Published in Journal Watch General Medicine June 8, 2004

Citation(s):

Thompson IM et al. Prevalence of prostate cancer among men with a prostate-specific antigen level 4.0 ng per milliliter. N Engl J Med 2004 May 27; 350:2239-46.

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• Medline abstract (Free)

Carter HB. Prostate cancers in men with low PSA levels -- Must we find them? N Engl J Med 2004 May 27; 350:2292-4.

• Original article (Subscription may be required)
• Medline abstract (Free)