Purpose: The surface bone-seeking radiopharmaceuticals rhenium-188-HEDP (188Re-HEDP) and samarium-153-EDTMP (153Sm-EDTMP) were investigated to determine the efficacy and toxicity in pain palliation in bone metastases.
Method: The effect of treatment with 188Re-HEDP and 153Sm-EDTMP on pain symptoms, life quality, and bone marrow function were obtained in 46 patients with prostate and breast cancer. There were 31 patients treated with 188Re-HEDP (3194+/-387 MBq) and 15 patients with 153Sm-EDTMP (2940+/-545 MBq). The 188Re-HEDP group included 6 patients and 25 patients, and the 153Sm-EDTMP group 6 patients and 9 patients with breast and prostate cancer, respectively. All patients had an interview using standardized sets of questions before and after therapy for 12 weeks. Blood counts were taken weekly for 6 weeks and after 12 weeks.
Results: After treatment with 188Re-HEDP, 77% of patients reported pain relief and 73% after 153Sm-EDTMP. Sixteen percent of the patients treated with 188Re-HEDP and 13% of those given 153Sm-EDTMP could discontinue their analgesics and were pain free. Patients described an improvement on the Karnofsky performance scale from 73+/-7 to 85+/-8% 12 weeks after 188Re-HEDP (p<0.05) and from 68+/-9 to 74+/-9% after 153Sm-EDTMP (p=0.217). Only 3 patients post-188Re-HEDP and 2 patients post-153Sm-EDTMP showed a thrombocytopenia below 100 x 10(3)/microl. The maximum nadir of platelet and leukocyte counts were observed between the second to fourth week after treatment in both and was reversible within 12 weeks. There were no significant differences in pain palliation, Karnofsky performance scale and bone marrow toxicity between the lower beta energy 153Sm-EDTMP and the higher beta energy 188Re-HEDP (p=0.098-0.442).
Conclusion: Both radiopharmaceuticals were effective in pain palliation, without induction of severe side effects or significant differences in therapeutic efficacy or toxicity.