Subset analysis of RTOG 85-31 and 86-10 indicates an advantage for long-term vs. short-term adjuvant hormones for patients with locally advanced nonmetastatic prostate cancer treated with radiation therapy

Abstract

Purpose: The benefit of adjuvant hormones in prostate cancer patients receiving definitive radiation therapy (RT) in RTOG 85-31 and 86-10 has previously been reported. This analysis excludes those patients with positive lymph nodes or postprostatectomy to determine the benefit of adjuvant hormones in men with locally advanced nonmetastatic prostate cancer receiving definitive RT. Methods and Materials: Nine hundred ninety-three eligible patients from RTOG 85-31 and 86-10 treated between 1987–1992 were included in this study. Five hundred seventy-five patients with T3N0M0 disease were included from RTOG 85-31 and 418 patients with T2b-T4N0M0 disease from RTOG 86-10. Patients randomized to receive long-term hormones (LTH) on 85-31 received goserelin starting the last week of RT and continued indefinitely. Patients treated with short-term hormones (STH) on 86-10 received goserelin and flutamide 2 months prior to and during RT. The median follow-up for all patients in this analysis was 71 months (range, 0.6–129 months). Results: Combining both studies, statistically significant improvements in outcome were observed between the RT and hormones (I) and RT alone (II) groups for biochemical disease-free survival (bNED control) and distant metastases failure (DMF). Statistically significant improvements in bNED control, DMF and cause-specific failure (CSF) were observed for patients receiving LTH compared with STH. In those patients receiving LTH, the benefit in bNED control ( p = 0.0002), DMF ( p = 0.05), and CSF ( p = 0.02) was limited to centrally reviewed Gleason score of 7 and 8–10 tumors. For all patients treated on 85-31, statistically significant improvements for bNED control, DMF, and CSF were observed between Group I and II. Multivariate analysis demonstrated Gleason score and the use of LTH to be independent predictors for bNED control ( p < 0.0001), DMF ( p < 0.0001), and CSF ( p < 0.002). Conclusions: Based on this analysis, adjuvant long-term hormones compared to short-term hormones resulted in statistically significant improvements in bNED control, DMF, and CSF rates for patients with locally advanced nonmetastatic prostate cancer.