Dynamic changes of bone metastasis predict bone‐predominant status to benefit from radium‐223 dichloride for patients with castration‐resistant prostate cancer

Background To best employ radium‐223 dichloride (Ra‐223) for patients with castration‐resistant prostate cancer (CRPC) and bone metastasis, we investigated the bone‐predominant status in patients treated with Ra‐223. Methods We retrospectively evaluated 127 CRPC patients who underwent treatment with Ra‐223. The patients were divided into three groups based on the types of dynamic changes of bone metastasis between diagnosis and just before Ra‐223: (a) only known lesions; (b) de novo lesions; (c) new progressive lesions. We developed the risk assessment using predictive factors based on progression‐free survival (PFS). Results During the median follow‐up period of 10.4 months, the median PFS in the only known lesions group was 11.3 months compared to 8.1 months in the de novo lesions group and 5.1 months in the new progressive lesions group (P 1 (HR 1.74, 95% CI 1.04‐2.89, P = .034), PSA value of >100 ng/mL (HR 1.59, 95% CI 1.02‐2.50, P = .043), and PSA doubling time (PSADT) of
We developed the risk assessment based on the types of dynamic changes of bone metastasis before the use of radium‐223 dichloride (Ra‐223). This risk assessment can be used to maximize the clinical benefits of Ra‐223 treatment for bone‐predominant metastasis.