Efficacy of SM-153 radionuclide therapy for bone pain palliation in metastatic prostate cancer

Aim: Patients usually present with painful osteoblastic metastases to the skeleton not responding chemotherapy, radiotherapy and high doses of analgesics. The aim of this study is to evaluate the usefulness and efficacy of radionuclide therapy with Sm-153 in patients with prostate cancer presenting painful osteoblastic osseous metastases. Materials-Methods: In our study, 10 patients aged 59-80 (mean age=69±6.26 years) with osteoblastic osseous metastases of prostate cancer, treated in our unit between November 2011 and December 2012, were included. All the patients had undergone Tc-99m hydroxymethylenediphosphonate (HDP) bone scintigraphy documenting increased multiple osteoblastic activity in the painful sites. Images were obtained from anterior and posterior projection in a 128x128 matrix with double headed gamma camera (Infinia, GE, Tirat Hacermel, Israel) equipped with a low-energy all purpose parallel hole (LEHR) collimators. Patients were excluded from the study, when their hemoglobin<10g/dl, WBC<3.5x109/dL, platelet count <100x109/dL, treated with systemic chemotherapy or RT in six weeks, spinal cord compression, pathologic fractures, life expectancy less than 3 months. All patients were treated with Sm-153-EDTMP at a standard intravenous dose of 37 MBq/kg and were observed for toxicity and decrease in pain score using visual analog scale (VAS) once in a week up to 6 weeks. A bone scan with Sm-153-EDTMP was performed 4 hours post treatment. Results: There was a significant decrease in VAS score from the time of administration up to 6 weeks. Mean pain score was decreased from %79 to %15. Median duration of response to therapy was found to be 8-12 weeks. No serious acute adverse events were observed post-treatment period. When we evaluated hematotoxicity of Sm-153-EDTMP; 2 patients showed a reduced toxicity (grade 1 anemia and grade 0-1 WBC) and other 8 patients did not show hematological toxicity. There was no relationship between the number and/or severity of bone lesions at the beginning of therapy and at the six week. Finally, six of ten patients died from terminal cancer within the mean 31 week (8-56 weeks) observation period. Conclusion: In our study we conclude that, Sm-153 was found feasible, effective and safe radionuclide therapy for bone pain palliation and reduced the overall-long term cost of pain palliation while improving the quality of life in patients with metastatic prostate cancer.