Cytoreductive Radiotherapy Combined with Abiraterone in Metastatic Castration-Resistance Prostate Cancer: A Single Center Experience

Abstract

<jats:title>Abstract</jats:title> <jats:p><jats:bold>Background: </jats:bold>To investigate the potential benefit of cytoreductive radiotherapy (cRT) in metastatic castration-resistant prostate cancer (mCRPC) patients receiving abiraterone.<jats:bold>Methods: </jats:bold>From February 2014 to February 2019, 149 mCRPC patients treated with abiraterone were identified. Patients receiving cRT before abiraterone failure (AbiRT group) were matched by one-to-two propensity score to patients without cRT before abiraterone failure (non-AbiRT group).<jats:bold>Results: </jats:bold>The median follow-up was 23.5 months. Thirty patients (20.1%) were in the AbiRT group, whereas 119 patients (79.9%) were in the non-AbiRT group. The 2-year overall survival (OS) of patients managed by AbiRT, cRT after abiraterone failure, and no cRT was 89.5%, 72.0% and 72.0%, respectively (<jats:italic>P</jats:italic> = 0.001). On multivariate analysis, only AbiRT (HR, 0.17; 95%CI, 0.05–0.58; <jats:italic>P</jats:italic> = 0.004) and prognostic index (HR 2.71; 95% CI, 1.37–5.35; <jats:italic>P</jats:italic> = 0.004) were significant factors. After matching, AbiRT continued to be associated with improved OS (median OS not reached vs. 44.0 months, <jats:italic>P</jats:italic> = 0.009). Subgroup analysis revealed that patients aged ≤65 years (HR, 0.09; 95%CI, 0.01–0.65; <jats:italic>P</jats:italic> = 0.018), PSA ≤20 ng/mL (HR 0.29; 95% CI, 0.09–0.99; <jats:italic>P</jats:italic> = 0.048), chemotherapy-naïve upon abiraterone treatment (HR 0.20; 95% CI, 0.06–0.66; <jats:italic>P</jats:italic> = 0.008) and in intermediate prognosis groups (HR 0.13; 95% CI, 0.03-0.57; <jats:italic>P</jats:italic> = 0.007) had improved OS with AbiRT. <jats:bold>Conclusions:</jats:bold> cRT before resistance to abiraterone may improve survival in selected mCRPC patients: relatively young, chemotherapy-naïve, with a relatively low PSA level at the diagnosis of mCRPC.</jats:p>