High-Dose Adjuvant Radiotherapy After Radical Prostatectomy With or Without Androgen Deprivation Therapy

Purpose To retrospectively evaluate the outcome and toxicity in patients receiving high-dose (>69 Gy) adjuvant radiotherapy (HD-ART) and the impact of androgen deprivation therapy (ADT). Methods and Materials Between 1999 and 2008, 225 node-negative patients were referred for HD-ART with or without ADT to two large academic institutions. Indications for HD-ART were extracapsular extension, seminal vesicle invasion (SVI), and/or positive surgical margins at radical prostatectomy (RP). A dose of at least 69.1 Gy was prescribed to the prostate bed and seminal vesicle bed. The ADT consisted of a luteinizing hormone–releasing hormone analog. The duration and indication of ADT was left at the discretion of the treating physician. The effect of HD-ART and ADT on biochemical (bRFS) and clinical (cRFS) relapse-free survival was examined through univariate and multivariate analysis, with correction for known patient- and treatment-related variables. Interaction terms were introduced to evaluate effect modification. Results After a median follow-up time of 5 years, the 7-year bRFS and cRFS were 84% and 88%, respectively. On multivariate analysis, the addition of ADT was independently associated with an improved bRFS (hazard ratio [HR] 0.4, p = 0.02) and cRFS (HR 0.2, p = 0.008). Higher Gleason scores and SVI were associated with decreased bRFS and cRFS. A lymphadenectomy at the time of RP independently improved cRFS (HR 0.09, p = 0.009). The 7-year probability of late Grade 2–3 toxicity was 29% and 5% for genitourinary (GU) and gastrointestinal (GI) symptoms, respectively. The absolute incidence of Grade 3 toxicity was