To the Editor.
—An important question that is not addressed in the article by Dr Gann and colleagues1 is the potential harm that widespread PSA screening could cause. The authors found an overall sensitivity for prostate cancer detection by PSA testing of 46%, with a specificity of 91%. Put another way, 9% of all PSA test results were false positives.According to the authors, archival blood samples were available from 14 916 men. A total of 322 of them developed prostate cancer over the 10-year study period, and 170 of these 322 had a positive PSA test result. If all 14 916 men had had PSA determinations, we would have expected to find 1313 false-positive PSA results among the 14 594 patients who did not develop prostate cancer in addition to the 170 true-positive PSA results among the 322 patients who did develop prostate cancer. This gives the PSA
Marshall KG. The Utility of Prostate-Specific Antigen for Detecting Prostate Cancer. JAMA. 1995;274(8):607. doi:10.1001/jama.1995.03530080023020