Intermittent androgen-deprivation therapy in the management of castrate-resistant prostate cancer (CRPCa): Results of a multi-institutional randomized prospective clinical trial.

Abstract

131 Background: Patients who develop CRPCa typically continue on androgen deprivation therapy (ADT). Whether these patients need to remain on ADT has not been well studied. We conducted a multicenter randomized trial to compare intermittent versus continuous approach to ADT in CRPCa patients. Overall survival, health related quality of life (QOL) and cost were the main endpoints. We hypothesized that the intermittent approach would be cost-saving while maintaining similar oncologic and QOL outcomes. Methods: CRPCa patients were randomized 1:2 to continuous or intermittent luteinizing hormone releasing hormone agonists (LHRHa). Patients were followed with clinical assessments, laboratory investigations, and QOL questionnaires (EORTC QLQ-C30 or PROSQOLI) every 2 months. If the serum testosterone rose above castrate levels (1.75nmol/L), LHRHa were re-initiated. The study was designed to close if >50% of patients needed to restart ADT in the intermittent arm. Results: 31 patients were followed with a median follow-up of 26.8 months; 18 in the intermittent arm and 13 in the continuous. 12/18 patients on the intermittent arm were re-initiated on LHRHa at a median time of 17.9 months. There was no difference in overall or cancer-specific survival between the two arms. There was no statistically significant difference in QOL between the two arms at 0 and 12 months. The total mean costs at 24 months were significantly lower in the intermittent arm (3135 $CAD vs 8253 $CAD, p=0.0167) compared to the continuous arm largely due to the reduced costs of the LHRHa. Conclusions: We have observed that intermittent ADT in patients with CRPCa, using a testosterone of >1.75 ngmol/L as a trigger to re-initiate LHRHa, results in a substantial cost savings with no negative impact on oncologic and QOL outcomes. These findings need to be corroborated in a study with a larger sample size. [Table: see text]