Radiopharmaceuticals for Palliation of Bone Pain in Patients with Castration-resistant Prostate Cancer Metastatic to Bone: A Systematic Review

ContextThe majority of patients with castration-resistant prostate cancer develop bone metastatic disease. It is often challenging to optimally palliate malignant bone pain. In case of multifocal pain due to diffuse osteoblastic metastases, treatment with bone-seeking radiopharmaceuticals can be considered.ObjectiveThis systematic review evaluates the efficacy of different bone-seeking radiopharmaceuticals for palliation of malignant bone pain from prostate cancer.Evidence acquisitionThe PubMed (Medline) and Embase databases were searched for publications on 89-strontium-chloride (89Sr), 153-samarium-EDTMP (153Sm), 186-rhenium-HEDP (186Re), 188-rhenium-HEDP (188Re), and 223-radium-chloride (223Ra). Randomised controlled trials and prospective cohort studies were included. Metastatic bone pain had to be registered as outcome measure for prostate cancer patients separately.Evidence synthesisThis review included 36 articles of which 13 randomised trials and 23 prospective studies. Of all trials, 10 studies used 89Sr, 7 153Sm, 12 186Re, 2 188Re, and 2 223Ra; three reported on a combination of different radionuclides. Only a few trials contained a blinding procedure and several studies contained incomplete follow-up or lack of intention-to-treat analysis. It was not possible to calculate a pooled estimate of pain response to treatment with any of the radionuclides because different definitions of pain response were used.ConclusionsOverall, pain response percentages greater than 50-60% were seen with each radionuclide. Haematological toxicity was reported in 26 of the 36 studies and more than half of these trials stated no grade 3/4 leukopenia or thrombocytopenia occurred.Patient summaryIn this report we reviewed the efficacy of bone-seeking radionuclides for treating bone pain from metastatic prostate cancer. Overall, treatment with bone-seeking radionuclides resulted in pain responses greater than 50-60%.