[EFFECT OF NEW ANDROGEN RECEPTOR AXIS-TARGETED AGENTS ON SURVIVAL OF CASTRATION-RESISTANT PROSTATE CANCER]

(Background)The real world's effect of new androgen receptor axis-targeted agents (ARATs) on survival of castration-resistant prostate cancer (CRPC) remains unclear in Japan. (Aims)The primary aim was to determine the clinical benefit of ARATs on survival of CRPC patients. The secondary aim was to evaluate predictive factors affecting the survival of CRPC patients. (Patients and results)Among 236 patients treated with androgen deprivation therapy (ADT), 68 patients developed CRPC; two groups of 34 patients were treated with ARATs (A cases) or conventional ADT (V cases). In a median follow-up of 61.5 months, 20 A and 22 V cases died of cancer. Median survival time (MST) from diagnosis was 99 and 66 months for A and V cases, respectively, and MST from CRPC to death were 50.5 and 44.5 months, respectively. There were no significant differences between both cases. The hazard ratio for death from diagnosis or CRPC progression of the A cases to V cases was 0.711; 95% confidence interval (CI), 0.371 to 1.362; P = 0.3037, or 0.805; 95% CI, 0.434 to 1.491; P=0.4899, respectively. Multivariable analysis revealed that a unique and significant independent prognostic factor from diagnosis was time to CRPC. (Conclusions)In this small retrospective study, we could not determine the clinical benefit of new ARATs compared with conventional ADT on survival of CRPC patients, and a unique and significant independent prognostic factor from diagnosis was time to CRPC. We need to validate these results in a future multi-institutional study.