Prostate-specific antigen (PSA) and radiotherapy in locally confined prostate cancer.

BACKGROUND

During the last 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 during and after radiotherapy of prostate cancer.

PATIENTS AND METHODS

From 1/95 to 6/97, 26 patients were irradiated for locally confined prostate cancer (11/26 patients primarily and 15/26 patients after radical prostatectomy). Radiation therapy was carried out with a linear accelerator with a total dose of 60 Gy to the prostate bed. PSA values were measured immediately before, weekly during radiation therapy and every three months after in the usual follow-up pattern.

RESULTS

During radiotherapy, median PSA values fell and continued to fall after radiotherapy. The median PSA half-life was reached 3 months after irradiation, the PSA nadir after 15 months. 5 patients with increasing PSA levels relapsed.

DISCUSSION

During and after radiotherapy, PSA kinetics are low with a median half-life of 3 months in our patient population. Rising PSA profile indicates progression of tumor.