The relation between bone pain response and skeletal metastases in cancer patients receiving ¹⁵³Samarium- EDTMP therapy

Objectives to elaborate if there is a relation between bone pain response and gender,type of cancer,patients age, number, extent of the bone lesions and number of ¹⁵³ Sm-EDTMP therapeutic doses in patients underwent 153Sm- EDTMP therapy for painful metastatic bone lesions of prostate and breast cancer

Methods 110 patients were included in this analysis, 63(57.3%) prostate males and 47(42.7%) breast females. Conventional whole body Tc-99m methylenediphosphonate (MDP) bone scan(to confirm bone metastases), relevant blood counts, detailed assessment of pain symptoms, analgesic consumption were obtained from all patients before receiving ¹⁵³Sm-EDTMP therapy. ¹⁵³Sm-EDTMP administration was performed according to the Vienna protocol developed at the Department of Nuclear Medicine, Vienna, Austria.

Results In patients who showed regression or stabilization in scintigraphy, a very good pain response to the repeated doses of therapy was observed (100%), while in the patients showed progression in scintigraphy, the response was moderate (83.4%) in breast cancer and 92.4% in prostate cancer. Regarding the patients who received only a single dose of the therapy, we noticed a good pain response (100%, 73.3%) among breast and prostate cancer patients who had > 10 bone lesions detected by scintigraphy, with a reasonable response (75%, 66.6%) among the patients who had <10 lesions, respectively.

Conclusions Our results indicate that ¹⁵³Sm-EDTMP provided a complete pain palliation in about 60% of patients with painful metastatic dissemination, a partial one in about 30% and no response only in less than 10%. ¹⁵³Sm-EDTMP therapy- induced pain response is not related to the type of cancer, gender, patients age and the number of therapeutic doses, however, pain response shows significant relation to the extent of bone lesions. This explains a high response rate (100%) in patients who showed scintigraphic regression. Repeated doses of ¹⁵³Sm-EDTMP offer a significant palliative benefit to cancer patients with metastatic bone pain.