Histopathology of castration-resistant prostate cancer confirms changes in bone metastasis during radium-223 treatment: A case report.

Radium-223 is used for treating castration-resistant prostate cancer with bone metastases. Here, we report the case of a 76-year-old man diagnosed with castration-resistant prostate cancer with bone metastases who was started on radium-223. Although the patient ultimately died from causes unrelated to the treatment before starting the third treatment course, we observed that radium-223 was more effective in areas closer to the bone cortex than in deeper tumor regions. Through histopathological analysis, we provide important mechanistic insights on the therapeutic effect of radium-223 in human prostate cancer bone metastases.