Prostate-specific antigen 1.5-4.0 ng/mL: a diagnostic challenge and danger zone.

UNLABELLED: What's known on the subject? and What does the study add? Large population screening trials like the ERSPC, PCPT and PLCO have noted that men with seemingly low PSA (even as low as 0.5 ng/dL) still can have prostate cancer. Despite these findings, PSA is still predominantly used as a current indicator for possible presence of prostate cancer rather than also serving as a prognostic marker. This study examines a larger number of men in a diverse US population to determine the prognostic value of a man's baseline or first PSA.

OBJECTIVES: • To assess the value of a PSA threshold of 1.5 ng/mL as a predictor of increased prostate cancer risk over a four-year period based on a man's first PSA test, including racial differences. • To review the risk of progression of benign prostatic hyperplasia (BPH) based on a similar PSA threshold.

PATIENTS AND METHODS: • A retrospective review involving 21,502 men from a large Midwestern health system was performed. • Men at least 40 years old with baseline PSA values between 0 and 4.0 ng/mL and at least four years of follow-up after initial PSA test were included. • Optimal PSA threshold and predictive value of PSA for development of prostate cancer were calculated.

RESULTS: • Prostate cancer rates were 15-fold higher in patients with PSA ≥1.5 ng/mL vs patients with PSA <1.5 ng/mL (7.85% vs 0.51%). • African American patients with baseline PSA <1.5 ng/mL faced prostate cancer rates similar to the whole study population (0.54% vs 0.51%, respectively), while African American patients with PSA 1.5-4.0 ng/mL faced a 19-fold increase in prostate cancer.

CONCLUSION: • Both Caucasian and African American men with baseline PSA values between 1.5 and 4.0 ng/mL are at increased risk for future prostate cancer compared with those who have an initial PSA value below the 1.5 ng/mL threshold. • Based on a growing body of literature and this analysis, it is recommended that a first PSA test threshold of 1.5 ng/mL and above, or somewhere between 1.5 and 4.0 ng/mL, represent the Early-Warning PSA Zone (EWP Zone). • This should serve to inform patients and clinicians alike to future clinical activities with respect to prostate cancer and BPH.