Long-term androgen deprivation, with or without radiotherapy, in locally-advanced prostate cancer: updated results from a phase III randomized trial.

We previously reported results of a randomized trial comparing androgen-deprivation therapy (ADT) combined with external beam radiation therapy (EBRT) and ADT alone in patients treated with locally advanced prostate cancer. We report here long-term oncological outcomes.

In this multicenter phase III trial, patients were randomly assigned to ADT alone or ADT+EBRT. Leuprorelin 11.25 mg was administered for three years. The whole pelvis was treated at a dose of 46Gy and the prostate with a boost from 20Gy to 28Gy. Primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS), disease-specific survival (DSS), locoregional progression free survival (LPFS), metastasis-free survival (MFS), biochemical progression free survival (BPFS) and tolerance.

With a median follow-up of 7.3 years, 263 patients were included. The 8-year PFS rate was significantly higher in the ADT+EBRT arm than in the ADT arm (48% versus 7%; hazard ratio: 0.27; 95%CI: (0.17;0.39), p<0.0001) (hazard ratio [HR] = 0.10; 95%CI: (0.05; 0.20); p < 0.0001 in patients with baseline PSA ≥ 50ng/ml and HR = 0.28; 95%CI: (0.19; 0.40), p < 0.0001 in patients with baseline PSA < 50ng/ml). The risk of death from prostate cancer was significantly reduced for ADT+EBRT arm (sub-hazard ratio (SHR): 0.48; 95%CI: (0.25; 0.91); p=0.02). The 8-year OS rate was respectively 57% in the ADT arm and 65% in the ADT+EBRT arm (no significant difference). LPFS was significantly in favor of ADT+EBRT arm (SHR = 0.61; 95%CI: (0.42; 0.89); p=0.01). MFS was comparable between both arms (p=0.88). Analysis of toxicities revealed acute lower tolerance in the ADT+EBRT arm with a gradual decrease in intensity from 6 months after the end of EBRT.

These long-term results confirm the oncological benefit of combining EBRT with ADT in the treatment of locally advanced prostate cancer. This article is protected by copyright. All rights reserved.

BJU international. 2019 Apr 04 [Epub ahead of print]

Paul Sargos, Nicolas Mottet, Carine Bellera, Pierre Richaud

Department of Radiation Oncology, Institut Bergonié, Bordeaux, France., Department of Urology, University Hospital, Saint-Etienne, France., Clinical and Epidemiological Research Unit, Institut Bergonié, Bordeaux, France.