Prostate-specific antigen testing of older men

Background: Elevated serum prostate-specific antigen (PSA) levels are predi ctive of a future diagnosis of prostate cancer. To test the hypothesis that older men with low PSA levels may require less intensive PSA testing becau se of a reduced prostate cancer detection rate, we evaluated the associatio n between age, baseline PSA level, and prostate cancer detection. Methods: We conducted a prospective cohort study among participants in a study of ag ing who had serial PSA measurements taken from age 60 or 65 years until the y either were diagnosed with prostate cancer (cancer case subjects) or reac hed the age of 75 years (subjects without prostate cancer). The time of can cer detection among cancer case subjects was defined as the measurement dat e on which a PSA level above 4.0 ng/mL was detected (i.e., PSA conversion), Cancer case subjects and subjects without prostate cancer were analyzed ac cording to baseline PSA level and age. Results: All cancer case subjects in the 60-year-old cohort had baseline PSA levels above 0.5 ng/mL, and 14 of 15 cancer cases that would have been detected by a PSA conversion among the 65-year-old cohort were associated with baseline PSA levels of 1.1 ng/mL o r more. If PSA testing were discontinued in men aged 65 years with PSA leve ls of 0.5 ng/mL or less, 100% (95% confidence interval [CI] = 78%-100%) of the cancers would still be detected by age 75 years; if PSA testing were di scontinued in men aged 65 years who had PSA levels of 1.0 ng/mL or less, 94 % (95% CI = 70%-100%) of the cancers would still be detected by age 75 year s. Conclusions: These data suggest that a decrease in the intensity of scre ening among older men with low PSA values may not lead to an increase in un detected prostate cancer.