The development and validation of a nomogram and calculator for survival among men treated with abiraterone acetate and/or enzalutamide for metastatic castration-resistant prostate cancer

Abstract Background With widespread medication choices for metastatic castration-resistant prostate cancer (mCRPC) is now available, on the other hand biomarker to predict the efficacy of each mCRPC treatment has not been established. This study developed prognostic nomogram and calculator to predict prognosis in mCRPC patients who received abiraterone acetate (ABI) and/or enzalutamide (ENZ). Methods A total of 568 mCRPC patients received ABI and/or ENZ from 2012 to 2017 were enrolled in this study. We developed prognostic nomogram based on the risk factors by Cox proportional hazards regression model. The nomogram was also assessed for discriminatory ability with the concordance index (C-index). We repeated 5-fold cross-validation 2000 times to estimate the C-index and reported the means of the estimated C-index for the training and validation sets. And we also developed nomogram calculator based on this nomogram. Results The median overall survival (OS) was 24.7 months. A multivariable analysis showed that the time to CRPC, pre-chemotherapy, baseline prostate-specific antigen (PSA), baseline alkaline phosphatase (ALP), and baseline lactate dehydrogenase (LDH) were independent risk factors for the OS (hazard ratio [HR]: 0.521, 1.681, 1.439, 1.827, 12,123, p:0.001, 0.001, <0.001, 0.019, <0.001)). C-index was 0.72 in training cohort and 0.71 in validation cohort. Conclusion We developed nomograms and calculator to predict the OS for Japanese mCRPC patients who received ABI and/or ENZ. The advent of mCRPC prognosis prediction calculator will facilitate greater accessibility for clinical use.