Adding 6 months of androgen suppression (AS) to external beam radiation therapy (EBRT) for localized intermediate-risk prostate cancer increases long-term event-free and disease-free survival, according to a recent study.
Compared with EBRT alone, EBRT plus 6 months of concomitant or adjuvant AS was significantly associated with a 47% decreased risk for primary endpoint events (PSA relapse, clinical relapse, start of second-line treatment in the absence of per-protocol progression, or death) and 33% decreased risk for any clinical relapse or death, Michel Bolla, MD, of Grenoble University Hospital in Grenoble, France, and colleagues reported in the Journal of Clinical Oncology.
Their analysis included 481 patients with intermediate-risk prostate cancer (stage cT1b-c or T2a with a PSA level of 10 ng/mL or higher or Gleason score 7 or less and a PSA level of 20 ng/mL or less, and no nodal involvement or metastasis) who participated in the EORTC (European Organisation for Research and Treatment of Cancer) Trial 22991 (NCT00021450). Of the 481 patients, 245 received EBRT plus AS (goserelin and bicalutamide) and 236 received EBRT alone. Patients received 74 or 78 Gy of conventional EBRT.
At a median follow-up of 12.2 years, 92 (37.6%) of 245 patients in the EBRT plus AS arm and 132 (55.9%) of 236 patients in the EBRT-only arm had events, mostly PSA relapse (48.7%) or death (45.1%), Dr Bolla’s team reported.
At 10 years, the distant metastasis-free survival rate was 79.3% with EBRT plus AS and 72.7% with EBRT alone; the overall survival rates were 80.0% and 74.3%, respectively. These between-group differences did not reach statistical significance, according to the investigators.
Bolla M, Neven A, Maingon P, et al. Short androgen suppression and radiation dose escalation in prostate cancer: 12-year results of EORTC Trial 22991 in patients with localized intermediate-risk disease. J Clin Oncol. Published online July 26, 2021. doi:10.1200/JCO.21.00855