Adjuvant and salvage radiation therapy after radical prostatectomy for adenocarcinoma of the prostate.

Abstract

To evaluate the outcome of adjuvant and salvage radiotherapy (RT) after radical prostatectomy (RP) for clinically localized prostate cancer using conventional clinical end-points, and the biochemical relapse-free rate (bRFR). Between 1987 and 1994, 113 node negative, hormonally naïve men received RT 1 month to 12 years after RP. Adjuvant RT was given for positive resection margins and/or pT3 disease. Salvage RT was given for a persistently elevated prostatic specific antigen (PSA), a rising PSA, or palpable recurrence post RP. Clinical and biochemical endpoints determined outcome. Log-rank testing and the Cox proportional hazards model identified factors predictive for biochemical relapse free rate. Median follow-up after RT was 3.7 years (range 0.2-9 years). Five-year clinical local control was 95% for patients with no palpable evidence of disease and 59% for those with palpable recurrence (P < 0.0001). 5-year bRFR was 81% for adjuvant RT, 19% for salvage of biochemical recurrence, 0% for patients with palpable disease (P < 0.0001). Improved bRFR for adjuvant and salvage RT was predicted by a Gleason score < 7 vs. 7 vs. > 7 (hazard ratio 1.53; 95% CI 0.99-2.35) and an undetectable pre-RT PSA vs. PSA < 2.0 ng/ml vs. PSA > 2.0 ng/ml (hazard ratio 3.81; 95% CI 2.47-5.87). Seminal vesicle involvement was not a statistically significant independent predictor of bRFR. The most favourable bRFR was observed for adjuvant therapy. Salvage was most successful with a pre-RT PSA < 2.0 ng/ml, or Gleason score < 7. Few patients with a pre-RT PSA > 2.0 ng/ml were salvaged, and none with palpable recurrence. These patients require investigation of alternative salvage strategies.