Radiation Escalation and Short-Term Androgen Suppression in Prostate Cancer
Posted: Friday, September 3, 2021
An article published in the Journal of Clinical Oncology recently highlighted the effects of irradiation and short-term androgen suppression in patients with intermediate-risk prostate cancer. Lawrence Collette, PhD, of the European Organisation for Research and Treatment of Cancer (EORTC), Brussels, and colleagues examined whether irradiation alone or irradiation plus androgen suppression influenced event-free survival and overall survival in patients with prostate cancer. Their long-term follow-up results revealed that 6 months of concomitant and adjuvant androgen suppression improved event-free and disease-free survival outcomes following irradiation; however, there were no apparent benefits in terms of overall and distant metastasis–free survival.
A total of 819 patients were randomly assigned in a 1:1 ratio between external-beam radiotherapy and external-beam radiotherapy plus androgen suppression groups. Patients were a part of the EORTC trial 22991 and were followed for approximately 12 years. External-beam radiation was delivered once a day (74 or 76 Gy), and androgen suppression consisted of two subcutaneous injections of three monthly depot of luteinizing hormone-releasing hormone analog given the first day of irradiation and then 3 months later. The primary endpoint of event-free survival was defined from study entry until first relapse. The secondary endpoints were clinical disease-free survival, overall survival, and distant metastasis–free survival.
Overall findings revealed that event-free survival was 68.1% with radiation plus androgen suppression (95% confidence interval (CI) = 61.6%–73.7%) and 49.3% withe radiation alone (95% CI = 42.4%–55.8%), corresponding to an observed hazard ratio (HR) of 0.53 (95% CI = 0.41–0.70; P < .001). The 10-year disease-free survival was 76.2% with radiation plus androgen suppression (95% CI = 70.1%–81.3%) and 66.0% with radiation alone (95% CI = 59.2%–71.9%), corresponding to an HR of 0.67 (95% CI = 0.49–0.90; P = .008). Dr. Collette and colleagues concluded that although there were no statistical differences across both groups for overall survival, radiotherapy plus androgen suppression led to improvements in event-free and disease-free survival.
Disclosure: For full disclosure of the study authors, visit ascopubs.org.
