Biochemical disease-free survival following adjuvant and salvage irradiation after radical prostatectomy

Abstract

Purpose : To present the biochemical cure rates (biochemically no evidence of disease) after external irradiation (RT) in patients with high-risk prostate cancer after radical prostatectomy. Methods and Materials : Seventy-six patients who underwent radical prostatectomy and subsequent RT were included in this analysis. No patient received hormonal therapy. Adjuvant RT was administered in 35 patients (46%), and 41 patients (54%) underwent salvage RT. After prostatectomy, the Gleason score was <7 in 87%, and 24% had seminal vesicle invasion. The median RT dose in the adjuvant RT and salvage RT groups was 60 Gy and 65 Gy, respectively. The biochemical cure rate was defined as a serum prostate-specific antigen of ≤0.2 ng/mL. Results : The overall 5-year Kaplan-Meier biochemical control rate from the end of RT was 70%. The 5-year biochemical cure rate for adjuvant RT was significantly superior to that after salvage RT (86% vs. 57%). The significant predictors of biochemical failure were seminal vesicle invasion in the adjuvant RT group and the presence of Gleason grade 4 or 5 in the salvage RT group. The clinical local control rate in the prostate bed was 100%. Conclusion : This report demonstrates the efficacy of RT in achieving high biochemical cure rates after radical prostatectomy. Additional clinical studies are required to determine the optimal treatment of patients at high risk of biochemical failure after postprostatectomy RT.