Samarium lexidronam (¹⁵³Sm-EDTMP): skeletal radiation for osteoblastic bone metastases and osteosarcoma

Abstract

Radiation therapy can be an effective means to treat bone metastases, which occur in more than 50% of cancer patients. ¹⁵³Samarium lexidronam (¹⁵³Sm-EDTMP; Quadramet, Cytogen) is a radiopharmaceutical designed for deposition into bone metastases. Bone scans can identify patients that may benefit from targeted radiation therapy with ¹⁵³Sm-EDTMP. As an unsealed source of radiation therapy, ¹⁵³Sm-EDTMP is simple to administer: 1 mCi/kg is given in a similar fashion to a bone scan injection (^99mTc-MDP bone scan injection is given at 0.2–0.35 mCi/kg. Therefore, both are administered intravenously. However, the radiation-absorbed dose and radiopharmaceutical energy are different). Nevertheless, despite simplicity of administration, ¹⁵³Sm-EDTMP is underutilized for improving cancer pain in the skeleton. Repeated cycles and combined treatment with other modalities such as bisphosphonates, chemotherapy and/or external beam radiation are possible. ¹⁵³Sm-EDTMP combined with bisphosphonates, chemotherapy and/or radiation may provide better palliation of bone metastases and also in bone-forming tumors (osteosarcoma). Encouraging experience using high-dose ¹⁵³Sm-EDTMP for total marrow irradiation in hematologic malignancies involving the bones (e.g., myeloma or acute leukemia) is also reviewed.

Keywords::

• ¹⁵³Sm-EDTMP
• bone cancer
• bone pain
• bone scan
• breast cancer chemotherapy
• external beam radiotherapy
• lesion irradiation
• leukemia
• marrow radiation
• metastatic cancer
• myeloma
• osteoblastic osseous metastases
• osteosarcoma
• prostate cancer
• radiation
• radiosensitization
• samarium
• scintigraphy
• skeletal metastases

Acknowledgements

The authors would like to acknowledge William Goeckeler (Cytogen) for providing ¹⁵⁴Eu information and perspectives related to ¹⁵³Sm-EDTMP production and nuclear decay chemistry.

Financial & competing interests disclosure

The assistance of Cytogen in providing an unrestricted educational grant to the Department of Pediatrics at MD Anderson Cancer Center is acknowledged. The assistance of the Ragnar Thorrison Research fund, Mike Dorian Legends of Friendswood sarcoma fund and the Departments of Pediatrics at MD Anderson Cancer Center is also acknowledged and greatly appreciated.

The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.