To the Editor.
—The recent article by Dr Gann and colleagues1 has provided an important service by determining the sensitivity and specificity of the PSA test in an unselected, if not typical, population of US men. However, there was no mention in the article of the PPV or NPV of the PSA. This is particularly surprising given that they also had the data to determine the prevalence of prostate cancer in this population.There were 366 cases of prostate cancer among 14 916 physicians (prevalence, 0.0245) who returned PSA samples. With a sensitivity of 73% for all cancers and a specificity of 91%, the PPV for all cancers is only 17%. (The prevalence of all prostate cancers among the 22 071 physicians from whom the smaller group was drawn was almost identical with a prevalence of 0.0236.) Similarly, there were 183 aggressive cancers among these 14916 physicians for a
The Utility of Prostate-Specific Antigen for Detecting Prostate Cancer. JAMA. 1995;274(8):607-608. doi:10.1001/jama.1995.03530080023021