Prostate-specific antigen testing of older

levels are predictive of a future diagnosis of prostate cancer. To test the hypothesis that older men with low PSA levels may require less intensive PSA testing because of a reduced prostate cancer detection rate, we evaluated the association between age, baseline PSA level, and prostate cancer detec-tion. Methods: We conducted a prospective cohort study among participants in a study of aging who had serial PSA measurements taken from age 60 or 65 years until they ei-ther were diagnosed with prostate cancer (cancer case sub-jects) or reached the age of 75 years (subjects without pros-tate cancer). The time of cancer detection among cancer case subjects was defined as the measurement date on which a PSA level above 4.0 ng/mL was detected (i.e., PSA conver-sion). Cancer case subjects and subjects without prostate cancer were analyzed according to baseline PSA level an