[Analgesic response and secondary effects in patients with osteoblastic metastasis, treated with Samarium 153 ethylenediaminotetramethylenephosphate].

BACKGROUND

Samarium153 EDTMP, a beta and gamma emitter, is used in the palliative therapy of painful bone metastases.

AIM

To evaluate the analgesic effects and myelotoxicity of Samarium153 EDTMP in patients with prostate, breast and renal carcinoma.

PATIENTS AND METHODS

Twenty patients with bone metastases (11 males), aged 65 years old as a mean, received a 1 to 2 mCi/kg intravenous dose of Samarium153 EDTMP, produced in Chile. Patients were followed thereafter during 4 to 40 weeks. Pain was assessed using a visual analogue scale.

RESULTS

Pain decreased from a score of 6.4 prior to treatment, to 2.7 at the fourth week of therapy and the effect lasted a mean of 12.5 weeks. Myelotoxicity was observed in 68% of cases (WHO stage I in 21%, stage II in 37%, stage III in 11% and no patients in stage IV). Platelets were the most affected series and neutrophils the least affected. Cell counts returned to normal between the sixth and eighth week. Seventy nine percent of patients decreased their basal analgesic therapy at the sixth week and 88% did so at the eighth week. Forty one percent of these patients discontinued all analgesics.

CONCLUSIONS

Samarium153 EDTMP is effective in the treatment of pain in patients with bone metastases and its myelotoxicity is low to moderate. It should be considered as a therapy for this type of pain, with the precaution of performing periodical bood counts.