The Optimal Efficacy of a Single Therapeutic Dose of Sm- 153 EDTMP in the Treatment of Painless Skeletal Metastases

Background: Sm-153 EDTMP is a widely accessible radiopharmaceutical for systemic radionuclide therapy in cancer patients with painful skeletal disseminations; its use is expressed to any metastatic bone lesions which has been avid to Tc-99m MDP. In this study we obtained a clinical experience with a single therapeutic dose of Sm-153 EDTMP on cancer patients showed painless bone metastases on conventional bone scintigraphy, its bone response so far has not been studied in a large number of patients. Objective: evaluation of the overall therapeutic bone response in 103 cancer patients showed a painless skeletal metastases whom underwent a single therapeutic dose of Sm-153 EDTMP and elaborate if there is a significant difference in bone response depending on gender, patients age, pathology of primary cancer, number of the metastatic bone lesions. Methods: 103 patients were included in this retrospective analysis, 78(75.7%) males and 25(24.3%) females, their age range (19-92y, mea= ± SD=64.3 ± 13.7), their diagnosis were prostate (60.2%), breast(19.4%), lung(7.8%), other primaries(12.6%), 64.1% of cancer patients showed less than 10 bone lesions, 35.9% showed more than 10 bone lesions on conventional bone scintigraphy performed pretherapy. Results: Out of 103 cancer patients received a single dose of Sm- 153 EDTMP therapy, 67% (69/103) showed overall therapeutic bone stabilization/regression and 33% (34/103) showed bone progression, the rate of bone progression/regression showed a statistical significant difference among cancer patients dependent on their gender, age, type of cancer (P-values<0.005), while the rate of bone progression/stabilization differed significantly among those with more than 10 bone lesions as compared with patients showed less than 10 bone lesions on conventional bone scintigraphy. Conclusion: This study showed that as Sm-153 EDTMP offers a riskless and effective therapy options in patients with painful bone disseminations, it also provides encouraging results among those with painless skeletal metastases.