Prostate specific antigen after radiotherapy for prostate cancer: a reevaluation of long-term biochemical control and the kinetics of recurrence in patients treated at Stanford University.

ABSTRACT

PURPOSE: We evaluated prostate specific antigen (PSA) evidence for control of prostatic cancer after irradiation. MATERIALS AND METHODS: We studied 110 patients for whom more than 2 PSA measurements were obtained to establish trends and the initial measurement was done between April 1985 and January 1988. RESULTS: A total of 42 patients (38%) had stable, normal PSA levels with followup averaging 12.4 years (range 4.4 to 24.8). Increasing clinical stage or Gleason score correlated significantly with risk for PSA relapse, as did pretreatment PSA level. Short PSA doubling times were associated with distant metastasis rather than with local recurrence. CONCLUSIONS: We found that irradiation durably controlled 38% of prostatic cancers of various stages and grades and is unlikely to accelerate tumor growth.