Prostate Specific Antigen (PSA)

General Information

As a tumour marker for prostatic cancer, PSA demonstrates high tissue specificity and serum concentrations correlate well with tumour mass and clinical stage. However, elevated concentrations can not be considered diagnostic of prostatic cancer, as PSA can be elevated in 15% of patients with benign prostatic hypertrophy.

PSA is an accurate marker of response to treatment and for early detection of recurrent disease. PSA has a serum half life of about 3 days and should fall rapidly to normal or undetectable concentrations after successful radical prostatectomy.

The expression of PSA requires the presence of testosterone or dihydrotestosterone, and therefore, PSA concentrations may be unreliable in patients receiving hormone manipulation therapy.