Purpose: To determine the potential advantage of androgen ablation following standard external-beam radiation therapy in patients with locally advanced (clinical or pathologic T3; clinical or pathologic node positive) carcinoma of the prostate. Methods and Materials: In 1987 the RTOG initiated a Phase III trial of long-term adjuvant goserelin in definitively irradiated patients with carcinoma of the prostate. A total of 977 patients were accrued to the study of which 945 remain analyzable: 477 on the adjuvant hormone arm (Arm I); and 468 on the radiation only arm (Arm II) with hormones initiated at relapse. The initial results were reported in the Journal of Clinical Oncology in 1997. Results: With a median follow up of 5.6 years for all patients and 6.0 years for living patients local failure at 8 years was 23% for Arm I and 37% for Arm II (p < 0.0001). Distant metastasis was likewise favorably impacted with the immediate use of hormonal manipulation with a distant metastasis rate in Arm I of 27% and 37% in Arm II (p < 0.0001). Disease-free survival (NED survival) and NED survival with PSA of 1.5 ng/mL (bNED) or less were both statistically significant in favor of the immediate hormone arm (both p < 0.0001). Cause-specific failure was not statistically different with a cause-specific failure of 16% for Arm I and 21% in Arm II (p = 0.23). Overall survival was likewise not statistically different between two arms, with a 49% overall survival at 8 years in Arm I and 47% in Arm II (p = 0.36). Subset analysis of centrally reviewed Gleason 8–10 patients who did not undergo prostatectomy showed that for patients receiving radiation therapy plus adjuvant hormones there was a statistically significant improvement in both absolute (p = 0.036) and cause-specific survival (p = 0.019). Conclusions: Use of long-term adjuvant androgen deprivation in addition to definitive radiation therapy results in a highly significant improvement in regards to local control, freedom from distant metastasis, and biochemical free survival in unfavorable prognosis patients with carcinoma of the prostate.

Updated results of the phase III Radiation Therapy Oncology Group (RTOG) trial 85-31 evaluating the potential benefit of androgen suppression following standard radiation therapy for unfavorable prognosis carcinoma of the prostate