To the Editor.
—A colleague of mine approached me rather concerned because his most recent PSA level was 3.8 ng/mL. According to Dr Gann and colleagues,1 his risk for developing prostate carcinoma is eightfold greater than if his PSA level had been less than 1.0 ng/mL. His question was this: What do I do now?It is not intuitively obvious that the risk of developing prostate cancer is increased eightfold if the PSA level is between 3 and 4 ng/mL because, in the study by Gann et al, 37 (10.1%) of 366 patients with prostate cancer had a PSA level between 3 and 4 ng/mL, yet 29 (7.9%) of the 366 cancer patients had PSA levels of less than 1.0 ng/mL. One way to gain perspective on this discrepancy is to track what happens to a group of patients receiving screening. Using the proportions found in the study by
Meyerhoff J, Livingston EH. The Utility of Prostate-Specific Antigen for Detecting Prostate Cancer. JAMA. 1995;274(8):608. doi:10.1001/jama.1995.03530080023022