Factors predicting skeletal-related events in patients with bone metastatic castration-resistant prostate cancer

BackgroundSkeletal-related events (SREs) are common complications of bone metastatic castration-resistant prostate cancer (mCRPC). To the authors' knowledge, there are limited data regarding which factors predict SREs. The authors identified risk factors for SREs in men with bone mCRPC using characteristics commonly available in the medical record.MethodsData from 454 patients with nonmetastatic CRPC were identified from 2 Veteran Affairs Medical Centers from 2000 through 2013. Among these men, 233 (51%) developed bone metastases during follow-up and represented the study cohort. First occurrence of an SRE was abstracted from the medical records. A stepwise multivariable Cox model was used to select the strongest predictors of time to SRE.ResultsThe median age of the patients at the time of diagnosis of bone mCRPC was 75 years (interquartile range, 68-81 years), and there were 153 nonblack patients (66%). During follow-up (median, 7.8 months [interquartile range, 2.9-18.3 months]), 88 patients (38%) had an SRE. On univariable analysis, more recent year of metastasis (hazard ratio [HR], 0.91), prostate-specific antigen doubling time of ≥9 months versus