Aim: The breast cancer and the prostate cancer are considered as the most frequently occurred metastatic tumors in bones. The bone pain appears in majority of patients with metastases. One possibility how to reduce or to remove this pain is the administration of the radiotherapy to the place of metastases. The present medicine disposes of two ways how to administer radiotherapy in the place of metastases: externally irradiation (loco-regional or half-body) or intravenous administration of bone-seeking therapeutic radiopharmaceuticals. Material and Method: We introduced intravenous administration of 153Samarium-EDTMP in 57 patients (30 prostate cancer, 23 breast cancer, 4 renal cell carcinoma). Mean applied activity was 40 MBq per kg of patient’s body weight. Results: After 153Sm-EDTMP administration we observed pain relief of various degree in 75 % of patients for three months. 1 and 3 months after 153Samarium-EDTMP administration the following haematologic parameters changes were seen: a) 7 % reduction in red cell count in one month after administration, 15 % reduction after three months. b) 43 % reduction in leukocyte count in one month after administration, 24 % reduction after three months. c) 50 % reduction in platelet count in one month after administration, 23 % reduction after three months. In all three haematological profiles (red cells, leukocytes, platelets) we detected reduction of values after treatment with 153Samarium-EDTMP. This reduction culminates one month after administration and in three months leukocytes and platelets count was getting better. Conclusion: Myelosuppression was mild and temporary. No patients had grade 4 hematological toxicity and only three patients (5 %) had grade 3 hematological toxicity (National Cancer Institute Common Toxicity Criteria).

        Key words: Myelotoxicity - Bone metastases - 153Samarium-EDTMP