Results of the ADRRAD Trial of pelvic IMRT plus radium-223 in men with mHSPC metastatic to bone.

Abstract

136 Background: Radiotherapy to the Prostate in mHSPC improves overall survival (OS) and Progression free survival (PFS) for patients with low-volume-disease[1]. Radium-223 in metastatic castration resistant prostate cancer (mCRPC) improves OS [2]. We conducted a prospective phase 1/2 clinical trial in mHSPC, testing the combination of with LHRHa, concurrent pelvic radiotherapy and radium-223. Methods: Thirty patients were recruited with mHSPC; they had a minimum of 3 bone metastases (majority had > 20 bone mets), nil visceral metastases, PS0-1. Patients were encouraged to receive up front docetaxel. They were treated with ongoing LHRHa, pelvic radiotherapy aiming for 74Gy in 37 fractions to prostate PTV with 60Gy concomitantly delivered to pelvic nodal PTV. Concurrently, patients received radium-223, 55kBq/kg for 6 cycles q28 days; fraction 1 radiotherapy was synchronous with cycle 1 day 1 radium-223. Results: Median age was 63 years and 28 (93%) received at least 4 cycles of docetaxel. One patient received prostate only radiotherapy due to bowel constraints. Three patients had cycle 6 radium-223 omitted. At a median follow-up of 28 months, there have been 415 Adverse events, (3% Grade >3), and 6 serious adverse events (SAEs) ( 2 episodes of UTI, 1 each of cystitis non-infective, cardiac chest pain, pyrexia and AKI). Commonest AEs by number were: leucopenia, neutropenia, and diarrhoea. Ten SSE’s have occurred including 8 courses of palliative radiotherapy for bone pain, 1 course of radiotherapy for impending MSCC and 1 pathological fracture. At median follow up 28.0 months, median biochemical PFS is 17.9 months, median OS not yet reached. Conclusions: This trial shows clear tolerability and promising early efficacy data requiring further exploration in a randomised phase 3 trial. Clinical trial information: 2014-000273-39.