Effectiveness and complications of 188Re-HEDP in palliative treatment of diffuse skeletal metastases

Introduction: Bone metastases are the most common cause of cancer-related pain in various primary malignant tumors, most often, breast and prostate. 188Re-hydroxyethylidene diphosphonate (188Re-HEDP) is a new and less expensive bone seeking radiopharmaceutical with favorable physical characteristics of the radionuclide such as short half life of 16.9h, maximal β energy of 2.1 MeV with a 15% γ-component of 155 keV and easily available from an in-house 188W/188Re generator. The aim of this study is to evaluate the therapeutic efficacy and safety profile of bone palliative therapy following administration of 188Re-HEDP. Methods: Twenty patients with painful metastatic bone lesions secondary to breast, prostate, multiple myeloma, ampulla of vater and lung cancers received 1 mCi/kg of 188Re-HEDP. Four hours after treatment, post-therapy scintigraphy was performed. All patients were interviewed using a standard set of questions (visual analogue scale: VAS) concerning their pain relief before, and after therapy at weekly intervals for the first month and every 2 weeks for the following 4 months. The general condition of the patients was also evaluated by Karnofsky-index and ECOG (Eastern Cooperative Oncology Group) performance status. Hematologic profiles were recorded before treatment and every two weeks up to 8 weeks after treatment. Results: Overall pain relief was found in 68.8% of patients. Decreased from 8.37±2.12 to 5.68±2.98 at VAS was observed 4 weeks after treatment. The osteoblastic lesions (breast and prostate) showed rather similar response to the treatment. Mean platelet counts decreased in 6th week and returned to baseline level in 8th week. One patient showed grade III leukopenia without any serious complication. Conclusion: 188Re-HEDP is an effective radiopharmaceutical for metastatic bone pain palliation therapy. Side effects include mild and transient thrombocytopenia and leucopenia and no life threatening side effect is observed.