Effects of Samarium-153 EDTMP palliation therapy on painful skeletal metastases

Aim: Bone metastases are frequent complication of many malignant diseases. The pain and impairment of mobility deteriorate the life of patients. Palliation therapy by means of bone-seeking beta-emitter-labelled radiopharmaceuticals can improve the quality of their life. However, subsequent alterations of blood count can be limitation for the repeated treatment. Aim of this study was follow up favourable reactions and side effects after single administration of 153Sm-EDTMP. Material and methods: 53 patients with painful widespread bone metastases (29 prostate cancer, 20 breast cancer, 4 kidney carcinoma) received single dose of 153Sm-EDTMP. The extent and metabolic activity of metastases were verified by scintigraphy with 99mTc-MDP several weeks ago. Before injection of drug the blood was sampled (blood cells count, ALP, Ca, P, tumour markers) and the Karnofsky's performance status, pain score and analgesic score (WHO scale) were also determined. All examinations were repeated 1 and 3 months after injection. Applied activity of 153Sm was 40 MBq per kg of patient's body weight. Distribution of radiopharmaceutical was imaged by whole body scintigraphy next day. Results: No acute reactions were observed for all patients. Only sometimes the pain increased for a short term. One month after injection a significant analgesic effect was noticed in 47% of patients, partial in 28% and minimal and/or none in 25% patients. Significant analgesic effect was after three months in 42%, partial in 36% and minimal and/or none in 22%. Mean Karnofsky's index before treatment was 60%, 1 and/or 3 month after treatment was 70%. Mean analgesic score decreased from basal level 2.0 to 1.6 after 1 month and 1.7 after 3 months. Haematological examinations showed the reduction in count of erythrocytes 7% after 1 month to 14% after 3 months, of leucocytes 42% to 25% and of thrombocytes 50% to 22%. Control bone scintigraphies with 99mTc-MDP detected decrease of the metabolic activity of metastases in 17% of patients, without changes were 62% and a progression were in 21%. In the blood during 3 months was found a reduction of ALP in 57% of patients, none changes in Ca or P metabolism and a sporadic decrease of PSA or CA15-3 levels. Conclusion: We observed analgesic effect of various degrees in 78% of patients after single administration of 153Sm-EDTMP. Reductions of blood cells count were a small degree in erythrocytes, more significant, however, reversible in leucocytes and thrombocytes