The Tolerance and Therapeutic Efficacy of Rhenium-188 Hydroxyethylidene Diphosphonate in Advanced Cancer Patients with Painful Osseous Metastases

Purpose: This study evaluated the tolerance and therapeutic efficacy of rhenium-188 hydroxyethylidene diphosphonate ((188)Re-HEDP) in patients with different types of advanced cancer suffering from bone pain caused by osseous metastases. Methods: Sixty-four patients received a single injection of escalating doses of (188)Re-HEDP with various dosages. Vital signs were observed before and after treatment for 8 weeks; adverse effects and rebound pain were recorded within 8 weeks after injection. Blood counts, biochemical parameters, and electrocardiogram were also measured over a period of 8 weeks. Clinical follow-up studies including the bone pain score and the Karnofsky performance score were performed. Pain response was scored by a four-point pain-rating scale as complete, marked, mild, and no response. Results: No adverse effects or clinically significant changes in vital signs, electrocardiograms, and biochemical parameters in patients were observed, and there was no statistical change in alkaline phosphate levels in patients before or after treatment. The overall nadir of thrombopenia was at week 4, leucopoenia at week 3, and anemia at week 8. At week 8, the mean level of platelets and leukocytes returned to baseline levels. The pain score descended from 8.11 to 7.74 on the day of therapy, with a nadir of 4.89 at week 4, and up to 6.67 at week 8 after therapy (p<0.05). The Karnofsky performance score continually increased from 74.81 before therapy to 82.31 at 8 weeks (p<0.05). Pain palliation was reported by 73.33% of patients, with a mean duration of 6.85 weeks and a mean start time of 4.05 days. Of the specific tumor types, pain relief was achieved in 84.62% of patients with prostate cancer, 78.57% with breast cancer, 62.50% with lung cancer, and 55.56% with liver cancer. Conclusions: (188)Re-HEDP is a useful radiopharmaceutical agent for improving bone pain in patients with advanced cancer with painful bone metastases.