Samarium-153-ethylene diamine tetramethylene phosphonate, a beta-emitting bone-targeted radiopharmaceutical, useful for patients with osteoblastic bone metastases

John Longo,1 Stephen Lutz,2 Candice Johnstone1 1Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI, USA; 2Department of Radiation Oncology, Blanchard Valley Regional Cancer Center, Findlay, OH, USA Abstract: Bone metastases are prevalent among cancer patients and frequently cause significant morbidity. Oncology providers must mitigate complications associated with bone metastases while limiting therapy-related adverse effects and their impact on quality of life. Multiple treatment modalities, including chemotherapy, surgery, external beam radiation therapy, and radioisotopes, among others, have been recommended and utilized for palliative treatment of bone metastases. Radioisotopes such as samarium-153 are commonly used in the setting of multifocal bone metastases due to their systemic distribution, affinity for osteoblastic lesions, acceptable toxicity profile, and convenience of administration. This review focuses on samarium-153, first defining its radiobiologic and pharmacokinetic properties before describing many clinical trials that support its use as a safe and effective tool in the palliation of patients with bone metastases. Keywords: bone metastases, pain, radiopharmaceuticals, pain flare