PURPOSE: Samarium-153 ethylene diamine tetramethylene phosphonate (153Sm-EDTMP), a bone-seeking radiopharmaceutical, provides therapeutic irradiation to osteoblastic bone metastases. Because the dose-limiting toxicity of 153Sm-EDTMP is thrombocytopenia, a dose-escalation trial using peripheral-blood progenitor cells (PBPCs) or marrow support was conducted to treat metastatic bone cancer.

PATIENTS AND METHODS: Patients with locally recurrent or metastatic osteosarcoma or skeletal metastases avid on bone scan were treated with 1, 3, 4.5, 6, 12, 19, or 30 mCi/kg of 153Sm-EDTMP.

RESULTS: Thirty patients were treated with 153Sm-EDTMP. Transient symptoms of hypocalcemia were seen at 30 mCi/kg. Estimates of radioisotope bound to bone surfaces and marrow radiation dose were linear with injected amount of 153Sm-EDTMP. Cytopenias also occurred in all subjects and were dose-related. At day +13 after 153Sm-EDTMP, residual whole-body radioactivity was 1% to 65% of whole-body radioactivity considered safe for PBPC infusion, 3.6 mCi. After PBPC or marrow infusion on day +14 after 153Sm-EDTMP, recovery of hematopoiesis was problematic in two patients at the 30 mCi/kg dose infused with less than 2 × 106 CD34+/kg on day +14, but not in other patients. Reduction or elimination of opiates for pain was seen in all patients. Patients had no adverse changes in appetite or performance status.

CONCLUSION: 153Sm-EDTMP with PBPC support can provide bone-specific therapeutic irradiation (estimates of 39 to 241 Gy). Hematologic toxicity at 30 mCi 153Sm-EDTMP/kg requires PBPC grafts with more than 2 × 106 CD34+/kg to overcome myeloablative effects of skeletal irradiation. Nonhematologic side effects are minimal.

© 2002 by American Society of Clinical Oncology


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DOI: 10.1200/JCO.2002.20.1.189 Journal of Clinical Oncology 20, no. 1 (January 01, 2002) 189-196.

Published online September 21, 2016.

PMID: 11773169

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