Objective: To identify threshold values of prostate-specific antigen (PSA) levels and PSA velocity (PSAV) to optimize the assessment of the risk of prostate cancer in young men, as prostate cancer is detected increasingly in men aged <50 years.
Patients and methods: Data for a group of 12 078 men, including 1622 with prostate cancer, were retrieved from the Duke Prostate Center Database. Based on the latest date for a PSA assay, these men were divided into two age groups of <50 and >/= 50 years, with 904 and 11 174 men in each group, respectively. Receiver operating characteristic curves (ROC) of PSA and PSAV were calculated and the cancer risk was assessed.
Results: The prevalence of prostate cancer was 4.4% (40 men) for men aged <50 years and 14.2% (1582 men) for men aged >/= 50 years. For the group with cancer the median PSA in men aged <50 years was significantly lower than that in men aged >/= 50 (1.3 vs 6.3 ng/mL, P < 0.001). ROC curves of PSA and PSAV showed a breakpoint at a PSA level of 2.3 ng/mL and a PSAV of 0.60 ng/mL/year for men aged <50 years. Both the sensitivity and specificity in the younger group at a PSA level of 2.5 ng/mL were higher than in the older group.
Conclusions: In men aged <50 years the operating characteristics of PSA are more sensitive and specific than in older men. Diagnostic PSA levels in men aged <50 years are significantly lower than suggested by guidelines. Using a 2.0-2.5 ng/mL PSA level threshold for biopsy in men aged <50 years and a PSAV threshold lower than the traditional 0.75 ng/mL/year is reasonable in contemporary practice. Further studies are warranted to validate these thresholds.