Effectiveness and complications of 153Sm-EDTMP in palliative treatment of diffuse skeletal metastases

The aim of the present study was to evaluate the efficacy and safety profile of bone palliative therapy following administration of 153Sm-EDTMP in patients with intractable metastatic bone pain. Sixteen patients (9 male, 7 female) aged 29-80 years (57.3±16.7 years) with severe metastasis-related bone pain resistant to analgesic medications were enrolled in the study. All patients having multiple bone metastases, positive bone scans, and estimated life expectancy of more than 2-3 months were entered the study. All patients received intravenous injection of 1.5 mCi (56 MBq)/kg of 153Sm-EDTMP. Four subscales for the intensity of pain were recorded: one as the present pain score (PPS) and the other three as maximum pain score (Max PS), minimum pain score (Min PS) and average pain score (APS) over the last 24 hours. Also the mean value of these 4 subscales was calculated as the mean total pain score (MTPS). The pain mental interference (PMI) was also assessed in 9 separate. Seven patients with breast cancer (43.75%), seven with prostate cancer (43.75%), one with papillary thyroid carcinoma (6.25%) and one with malignant paraganglioma (6.25%) were included in the study. A significant response to therapy, i.e. 2-point reduction in pain score and/or remarkable reduction (³25%) in the equivalent narcotic dose, was observed in 11 out of 16 patients (68.7%) by the 2nd week and in 12 patients (75%) by the 8th week. Regarding the palliative response to treatment and equivalent narcotic dose reduction, no significant difference between two major types of underlying malignancies (breast and prostate cancer) was found. There was no significant difference regarding response to therapy between two genders and among different age groups. The severity of bone marrow suppression was graded ≤2 in all patients. Response to palliative treatment with 153Sm-EDTMP in prostate and breast cancers is the same at the rate of 75% at the end of 8th week post-infusion. Hematologic toxicity is mild to moderate and no life-threatening side effect is observed.