Short Androgen Suppression and Radiation Dose Escalation in Prostate Cancer: 12-Year Results of EORTC Trial 22991 in Patients With Localized Intermediate-Risk Disease

PURPOSE The European Organisation for Research and Treatment of Cancer (EORTC) trial 22991 ( NCT00021450 ) showed that 6 months concomitant adjuvant androgen suppression (AS) improves event- (EFS, Phoenix) clinical disease-free survival (DFS) intermediate- high-risk localized prostatic carcinoma, treated by external-beam radiotherapy (EBRT) at 70-78 Gy. We report the long-term results in intermediate-risk patients with 74 or 78 Gy EBRT, as per current guidelines. PATIENT AND METHODS Of 819 randomly assigned between EBRT plus AS started on day 1 481 entered intermediate risk (International Union Against TNM 1997 cT1b-c T2a prostate-specific antigen (PSA) ? 10 ng/mL Gleason ? 7 PSA 20 ng/mL, N0M0) had planned (342 patients, 71.1%) (139 28.9%). primary end point EFS, DFS, distant metastasis–free (DMFS), overall (OS) intention-to-treat stratified dose two-sided ? = 5%. RESULTS At a median follow-up 12.2 years, 92 245 132 236 EFS events arm, respectively, mostly relapse (48.7%) death (45.1%). improved DFS (hazard ratio [HR] 0.53; CI, 0.41 to 0.70; P < .001 HR 0.67; 0.49 0.90; .008). DMFS was 79.3% (CI, 73.4 84.0) 72.7% 66.2 78.2) (HR 0.74; 0.53 1.02; .065). With 140 deaths (EBRT AS: 64; EBRT: 76), 10-year OS 80.0% 74.1 84.7) 74.3% 67.8 79.7) but not statistically significantly different 1.04; .082). CONCLUSION Six irradiation effects did reach statistical significance.