Intermediate-Term Risk of Prostate Cancer is Directly Related to Baseline Prostate Specific Antigen: Implications for Reducing the Burden of Prostate Specific Antigen Screening

Abstract

Prostate specific antigen screening is controversial, as a large number of men must be screened annually to achieve a benefit. We sought to determine whether baseline prostate specific antigen could reliably predict subsequent risk of prostate cancer and risk of consequential prostate cancer. A multiethnic cohort of 2,923 prostate cancer-free men was recruited between 2000 and 2012, and followed for a median of 7.5 years. Baseline prostate specific antigen was stratified into 6 strata and relative hazards of prostate cancer detection for each prostate specific antigen stratum were estimated, adjusting for ethnicity, family history and age. During followup 289 patients were diagnosed with prostate cancer. Men with baseline prostate specific antigen in the lowest stratum (0.1 to 1.0 ng/ml) were at greatly reduced risk for prostate cancer during followup. This half of the cohort with prostate specific antigen 1.0 ng/ml or less were at 3.4% (95% CI 2.1, 4.5) 10-year risk of prostate cancer and 90% of the cancers were low risk. By comparison the other half were at 15% to 39% risk of cancer detection with a 39% risk in the highest stratum (3 to 10 ng/ml). Optimal prostate specific antigen screening frequency for men with aprostate specific antigen level of 0.1 to 1.0 ng/ml may be up to every 10 years. Thisapproach has the potential to dramatically reduce the cost of screening, decreasing over detection of inconsequential tumors, while maintaining detection of tumors for which treatment has been proven to reduce prostate cancer mortality.