Palliative therapy with samarium-oxabiphore, 153Sm for bone metastases. dose, efficacy, toxicity

Purpose: The purpose of this study is the evaluation of the efficiency of the Samarium-Oxabiphore, 153Sm in palliative therapy for bone metastases and the analysis of dose dependence, treatment response and toxicity. Materials and Methods: A total of 173 cancer patients (predominantly breast or prostate cancer) with painful bone metastases were treated. In 141 patients (group I), Samarium-Oxabiphore 153Sm was infused intravenously at the rate of 1.0 mCi (37 MBq)/1 kg body weight and in 32 patients (group II) - at the rate of 1.5 mCi (55.5 MBq)/1 kg body weight. Within 3 months pain score (according to a 10-point scale), life quality (by Karnovsky), change in the number of leukocytes and platelets were evaluated. Results: In the group I, treatment response of different degree occurred in 112 (79.4%) of 141 patients. The stable or slight response (decrease of pain intensity by 1 point) rate was 22.6% (32 patients), the partial response (decrease of pain intensity by 2 points) rate was 30.4% (43 patients) and the marked response (decrease of pain intensity by 3 and more points) rate was 27.1% (47 patients). Twenty-nine (20.8%) patients were non-responders. Karnovsky index increased, on the average, from 61.3% (before treatment) up to 70.4% (at 1 month) and up to 68.5% (at 3 months). In the group II, 26 of 32 patients (81.2%) were responders. The stable or slight response rate was 21.8% (7 patients), the partial response rate was 31.2% (10 patients) and the marked response rate was 28.1% (9 patients). Six patients (18.7%) were non-responders. Karnovsky index increased, on the average, from 62.1% (before treatment) up to 69.4% (at 1 month) and up to 68.9% (at 3 months). In the group I, the number of leukocytes decreased, on the average, from 5.2 x 109/L (before treatment) up to 2.4 x 109/L (at 2 weeks), 2.8 x 109/L (at 4 weeks), 3.6 x 109/L (at 6 weeks), 4.3 x 109/L (at 8 weeks) and 4.8 x 109/L (at 12 weeks). In the group II, the number of leukocytes averaged 5.4 x 109/L (before treatment), 1.9 x 109/L (at 2 weeks), 2.1 x 109/L (at 4 weeks), 3.2 x 109/L (at 6 weeks), 3.8 x 109/L (at 8 weeks) and 4.3 x 109/L (at 12 weeks). In group I, the number of platelets changed, on the average, as follows: 256, 2 x 109/L (before treatment), 140.4 x 109/L (at 2 weeks), 130.1 x 109/L (at 4 weeks), 148.2 x 109/L (at 6 weeks), 175.3 x 109/L (at 8 weeks) and 198.4 x 109/L (at 12 weeks). In the group n, the number of platelets averaged 248.2 x 109/L (before treatment), 130.1 x 109/L, (at 2 weeks), 97.6 x 109/L (at 4 weeks), 118.2 x 109/L (at 6 weeks), 132.6 x 109/L (at 8 weeks) and 168.3 x 109/L (at 12 weeks). Conclusion: Therapy with Samarium-Oxabiphore, 153Sm is effective for pain relief and improvement of life quality. In both groups (1.0 or 1.5 mCi (37 or 55.5 MBq)/l kg body weight) treatment response was similar, whereas dosage of 1.5 mCi (55.5 MBq)/1 kg body weight resulted in more marked side effects (leucopenia and thrombocytopenia). (authors)