Treatment of Metastatic Bone Pain with Rhenium-188 Hydroxyethylidene Diphosphonate

Abstract

Objective: This study was designed to evaluate the safety and effectiveness of rhenium-188 hydroxyethylidene diphosphonate (¹⁸⁸Re-HEDP) in patients with skeletal metastases. Methods: Thirty-two patient volunteers with cancer metastasized to bone were included in this study. All patients underwent bone scanning with technetium-99m methylene diphosphonate 2 days before the administration of ¹⁸⁸Re-HEDP. A dose of 1,110 MBq (30 mCi) of ¹⁸⁸Re-HEDP was injected intravenously and whole body dynamic scans were obtained 1, 2, 3, and 5 days later. Blood and urine samples were collected daily for 5 days and then weekly for 4 weeks. The biokinetic data were obtained and the radiation doses were calculated. The reactions, toxicity and pain relief were corrected. Results: No acute reaction or toxicity was evident. Leukopenia was found only in 1 patient with skeletal metastases from prostate cancer. The baseline white blood cell count of 4.3 × 10⁹/l (normal range 4.0–10.0) declined to a value of 3.0 × 10⁹/l 1 week after receiving 1,110 MBq (30 mCi) of ¹⁸⁸Re-HEDP. The white blood cell count had returned to the baseline category by 4 weeks after injection. No patient was found to be thrombocytopenic. The hemoglobin concentration remained at the baseline level for 6 weeks. The excretion rate of ¹⁸⁸Re-HEDP in the urine was 62% of the administered activity during the first 2 days. Twenty-eight of the 32 patients (87.5%) were able to reduce their analgesic intake. Twenty of the 32 patients (62.5%) had a significant improvement in the quality of life while 8 patients (25%) had a minor improvement. Conclusion: Most of the patients experienced an improvement in the quality of life without induction of serious bone marrow reduction with this treatment regime. It is therefore concluded that the use of ¹⁸⁸Re-HEDP for treatment of skeletal metastasis appears to be feasible.