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

Abstract

Purpose: 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).

Methods: 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.

Results: 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.

Conclusions: 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.