A single-center, multidisciplinary experience with radium-223 dichloride in men with metastatic castrate-resistant...

We aimed to investigate several clinical and biochemical parameters, including palliative external beam radiation therapy (EBRT) to predict survival in patients with metastatic castrate-resistant prostate cancer (mCRPC) treated with radium-223 (²²³Ra).

We tested known and possible prognostic parameters, including palliative EBRT, both prior and concurrent to ²²³Ra. Logrank test (Kaplan-Meier method) and Cox regression analysis were used to predict overall survival (OS).

A total of 133 patients were treated with ²²³Ra; median age was 72 years. Median OS was 9.0 (95% confidence interval [CI] 7.4-10.6) months. By univariate analysis (log-rank test), baseline Eastern Cooperative Oncology Group performance status (ECOG PS) 0-1 (p=0.001), ≥5 cycles of ²²³Ra (p<0.001), baseline hemoglobin (Hb) ≥120 g/L (p <0.001), baseline total alkaline phosphatase (tALP) <110 U/L (p=0.001), and any prostate-specific antigen (PSA) decline at week 12 (p=0.013) were associated with increased OS. EBRT prior and/or concurrent to ²²³Ra showed a trend (p=0.051) towards inferior OS by univariate analysis only. By multivariate analysis, significant factors were PS 0-1 (hazard ratio [HR] 1.94, 95% CI 1.3-2.9, p=0.001), Hb ≥120 g/L (HR 0.5, 95% CI 0.3-0.9, p=0.011), and absence of docetaxel use prior to ²²³Ra (HR 1.86, 95% CI 1.08-3.22, p=0.026). With baseline Hb, tALP, and ECOG PS, we were able to divide patients into three groups with different median OS (months): 23.0 (95% CI 12.8-33.2), 8.0 (95% CI 6.7-9.3), and 5.0 (95% CI 3.1-6.9) for low-, intermediate-, and high-risk, respectively (p<0.001).

We found that ²²³Ra therapy can result in an OS of close to two years in carefully selected patients. Earlier administration of ²²³Ra therapy to fitter patients with mCRPC should be tested.