Long-term versus short-term androgen deprivation combined with high-dose radiotherapy for localized prostate cancer: A Spanish multicenter phase III trial.

Abstract

e15036 Background: Controversy remains about the timing and optimal duration of AD when associated to high- dose radiotherapy (HDRT). The purpose of this trial is to determine whether long-term AD (LTAD) is superior to short-term AD (STAD) in the setting of HDRT. Methods: Patients with cT1c-T3aN0M0 adenocarcinoma of prostate with intermediate and high risk factors according to NCCN criteria and PSA less than 100 ng/ml were included. All patients received 4 months of neoadjuvant and concomitant AD (STAD) + HDRT (minimum dose to the prostate 76 Gy) before were they randomized to adjuvant AD (LTAD) with gosereline for two years. Stratification was performed according to risk group (intermediate risk [IR] versus high risk [HR]). Primary endpoints were biochemical-disease free survival (bDFS) and toxicity scores. As approved by the study's Data and Safety Monitoring Committee an early interim analysis of compliance and safety is reported here. Results: To date, 298 men have been enrolled out of a planned accrual of 358 patients of whom 270 were valuable for the present analysis. One-hundred thirty four were randomly assigned to LTAD (69 HR and 65 IR) and 136 to STAD (71 HR and 65 IR), p=1.0. Demographic data, tumor and treatment characteristics were evenly distributed in the two arms. The median follow-up was 21 months. Relevant adverse reactions attributed to AD and RT grade > 2 late toxicity are summarized in the Table. Four patients in the STAD arm (2 IR and 2 HR) have developed biochemical failure compared to no one in LTAD arm. Conclusions: The interim analysis of this ongoing study shows that the present trial is safe and feasible. Adverse effects AAD arm non ADD arm p value Attributed to AD Osteoporosis 3% 0% NS Myocardial infarction 1% 0% NS Attributed to RT Frequency urinate 14% 15% NS Incontinence 3% 0% NS Hematuria 0% 3% NS Urethral estenosis 2% 0% NS Diarrhoea 0% 1% NS Proctitis 0% 3% NS Rectal bleeding 4% 4% NS Abbreviations: AAD, adjuvant androgen deprivation; NS, not significant. No significant financial relationships to disclose.