223Ra Therapy in Patients With Advanced Castration-Resistant Prostate Cancer With Bone Metastases: Lessons from Daily Practice.

Purpose: To identify pre-therapeutic variables associated with overall survival (OS) in patients treated with Ra.

Methods: Data from 45 CRPC patients treated with Ra were retrospectively analyzed. All patients who received at least one Ra injection were included in the study. Cox proportional hazard regression models were used to estimate hazard ratio's (HR) and to test for association.

Results: Twenty-one patients (47%) received six Ra injections and 24 patients (53%) received one to five Ra injections. Median OS since start of Ra was 13.0 months (95% confidence interval (CI) 8.2-17.8). Patients who completed Ra therapy had a median OS of 19.7 months (95% CI 14.9-24.6), while patients who received one to five Ra injections had a median OS of 5.9 months (95% CI 3.8-8.1; P < 0.001).Univariable analysis showed poor baseline ECOG performance status (PS), baseline opioid use, lowered baseline hemoglobin, and elevated prostate-specific antigen, alkaline phosphatase and lactate dehydrogenase (LD) levels were significantly associated with OS. Multivariable Cox regression analysis demonstrated that poor baseline ECOG PS (HR 10.6) and high LD levels (HR 7.7) were pre-therapeutic variables that predicted poor OS.

Conclusions: In a multivariable Cox regression model, good baseline ECOG PS and low LD levels were significantly associated with longer OS in patients treated with Ra. These variables may be used for stratification of CRPC patients for Ra therapy. Prospective studies to evaluate these variables are warranted, to develop a nomogram to select patients properly. In this retrospective study, predictors of overall survival in 45 metastatic castration-resistant prostate cancer patients treated with Ra therapy were evaluated. Baseline ECOG performance status and lactate dehydrogenase levels turned out to be significant in a multivariable prediction model for overall survival.