Prostate-specific antigen (PSA) in the monitoring of prostate cancer after radical prostatectomy and external beam radiation

Background: During the last few years, prostate-specific antigen (PSA) has been established as the most important tumor marker for prostate cancer. The aim of our study was to evaluate the response of PSA after surgery and radiotherapy of prostate cancer. Patients and Methods: From 1/1995 to 9/1997, 32 patients were treated by radical prostatectomy and subsequent radiotherapy. Radiation therapy was carried out using a linear accelerator to the prostate bed, a total dose of 60 Gy was given. PSA values were measured immediately before irradiation, weekly during radiation therapy and every three months thereafter in the usual follow-up pattern. Results: 21 of 32 patients had no measurable PSA after surgery. In the remaining II patients the median PSA half-life was reached 3 months after irradiation, the nadir after 15 months. 5 patients with increasing PSA levels suffered from a relapse (15.6%). Conclusions: We found that PSA monitoring is a useful marker for treatment outcome and that adjuvant radiotherapy after surgery improves local control as well as biochemical failure rate. If PSA is still detectable after surgery the risk for biochemical failure is significantly higher (45.5%).