Purpose: Bone is a common site of metastatic disease and the most frequent site of metastatic spread in patients with prostate cancer. Most patients with bone metastases complain of bone pains. This pain may be alleviated or eliminated by administration of radiotherapy at the site of metastases. Currently, two forms of radiotherapy administration exist: external-beam irradiation or intravenous administration of bone-seeking therapeutic radiopharmacon such as samarium-153-ethylene-diamino-tetramethylene-phosphonate (EDTMP). This radiopharmacon produces beta-particles and concentrates in the areas of enhanced osteoblastic activity. The aim of this study was to assess the efficacy of (153)Sm-EDTMP therapy.
Materials and methods: 32 men (aged 50-83, mean 70 years) with bone disseminated hormone-refractory prostate cancer and bone pain received (153)Sm-EDTMP. Mean applied dosage was 40 MBq/kg of the patient's body weight. Karnofsky performance status, pain score (numerical rating scale), analgesic score (WHO) and blood count were evaluated before, and 1 and 3 months after the treatment.
Results: Significant pain relief was observed in 44 and 38% of patients, mild relief in 31 and 34% and no effect in 25 and 28% of patients, 1 and 3 months after administration, respectively. Pain palliation was accompanied by an improvement in mobility and a decrease in necessary dosage of analgesics. Mild and transient bone marrow suppression was observed as a side effect of (153)Sm-EDTMP treatment. None of the patients showed hematological toxicity grade 4, and only 2 showed grade 3 (NCI CTC). The majority of the patients had hematological toxicity grade 1 or 2.
Conclusion: After (153)Sm-EDTMP administration, bone pain palliation was observed in 72% of patients for 3 months. Hematological toxicity after (153)Sm-EDTMP treatment was mild and transient.