Short-term Androgen Deprivation Therapy and High-dose Radiotherapy in Intermediate- and High-risk Localized Prostate Cancer: Results from the GETUG 14 Randomized Phase 3 Trial.

Abstract

Few studies have compared short-term androgen deprivation (STADT) combined with high-dose radiotherapy (STADT-RT) versus high-dose radiotherapy (RT) alone in localized prostate cancer. The GETUG 14 study randomized 376 patients to RT (n = 191) or STADT-RT (n = 179). The RT dose was 80 Gy in both arms. STADT consisted of monthly triptorelin and daily flutamide for a total duration of 4 mo, starting 2 mo before RT. Disease-free survival (DFS) was the primary endpoint. Secondary endpoints were overall survival (OS), biochemical failure (BF), metastasis failure (MF), toxicity, and quality of life. Among the 370 patients in the modified intention-to-treat population, 241 (65%) had intermediate-risk and 107 (28%) high-risk prostate cancer. At median follow-up among surviving patients of 84 mo (interquartile range 62-99 mo), the 5-yr DFS rate was 76% in RT arm versus 84% in STADT-RT arm (hazard ratio [HR] 0.64, 95% confidence interval [CI] 0.43-0.94]). ADT addition decreased BF (HR 0.45, 95% CI 0.28-0.72) and MF (HR 0.5, 95% CI 0.23-1.11) but not OS (HR 1.22, 95% CI 0.65-2.29). There were no significant differences for RT versus STADT-RT in the incidence rates for grade ≥2 toxicity in terms of acute gastrointestinal (GI) toxicity (26%, 95% CI 20-32 vs 26%, 95% CI 20-33), acute genitourinary (GU) toxicity (39%, 95% CI 32-46% vs 42%, 95% CI 35-50%), late GI toxicity (21%, 95% CI 16-28% vs 23%, 95% CI 18-30%), or late GU toxicity (30%, 95% CI 24-38% vs 27%, 95% CI 21-34%). STADT is a well-tolerated and effective strategy that can enhance oncological outcomes when combined with high-dose RT, particularly for patients with intermediate- or high-risk prostate cancer.