Real-world Outcomes and Factors Predicting Survival and Completion of Radium 223 in Metastatic Castrate-resistant Prostate Cancer

Abstract

AimsTo analyse outcomes in metastatic castrate-resistant prostate cancer (mCRPC) patients treated with radium 223 (Ra-223) across the Yorkshire and Humber Cancer Network. Materials and methodsA regional, multicentre, retrospective cohort study of 189 men undergoing Ra-223 for mCRPC between March 2014 and April 2017 was undertaken. Factors predicting overall survival and completion of planned treatment were assessed. ResultsThe median overall survival for the entire cohort was 10.5 months. Those completing five to six cycles of Ra-223 had a higher overall survival of 18.6 months. On multivariable analysis, four factors remained independent significant predictors of overall survival: age (P = 0.005, hazard ratio 1.07 [1.02–1.12]); number of cycles of Ra-223: 5–6 versus 1–4 (P ≤ 0.001, hazard ratio 0.10 [0.005–0.20]); baseline alkaline phosphatase (P = 0.044, hazard ratio 1.06 [1.002–1.12]); neutrophil-to-lymphocyte ratio (P = 0.033, hazard ratio 1.19 [1.01–1.40]). Baseline performance status 0 versus 2 (P = 0.026, odds ratio 0.080 [0.001–0.74]) and higher baseline haemoglobin (P = 0.028, odds ratio 1.04 [1.004–1.074]) were independent predictors of the completion of five to six cycles of Ra-223. ConclusionsYounger age, completion of five to six cycles of Ra-223, lower alkaline phosphatase and neutrophil-to-lymphocyte ratio are predictors of overall survival. This is the first study to report neutrophil-to-lymphocyte ratio as an independent predictor of overall survival in a Ra-223 cohort. Good performance status and higher baseline haemoglobin predict the completion of five to six cycles of Ra-223.