Management of metastatic bone pain with repeated doses of rhenium 186-HEDP in patients under therapy with zoledronic acid: a safe and additively effective practice.

Purpose: The aim of this study was to compare pain response and hematologic toxicity between single and multiple therapies with (186)Re-HEDP under zoledronic acid in patients suffering from painful osseous metastases from prostate or breast cancer.

Materials And Methods: Forty-five (45) patients received multiple therapies of (186)Re-HEDP (n = 77), under a stable regimen of analgesics and zoledronic acid, far off other therapeutic manipulations, and with no extraosseous disease progression. Hematologic status and pain indices were followed up regularly.

Results: Evaluable patients (n = 12), received 31 (186)Re-HEDP therapies. After the first treatment with (186)Re-HEDP, the mean percentile decrease for hemoglobin was 4.7%, for white blood cells was 21.4%, and for platelets was 12%. After multiple therapies, the respective declines were 7.0%, 16.0%, and 23.4%. With respect to baseline blood counts, only thrombocytes showed a tendency for greater decrease after repeated treatments, yet not of clinical significance. Favorable clinical response occurred after the first therapy in 10 of 12 patients (83.3%), after multiple doses in 15 of 19 (78.9%), and overall in 25 of 31 (80.6%) of (186)Re-HEDP therapies. Significant post-therapy improvement in pain indices was observed in all cases, regardless of the number of therapeutic doses.

Conclusions: Retreatments with (186)Re-HEDP under zoledronic acid provide continuing effectiveness in metastatic bone pain and are safe enough, if an acceptable baseline hematologic status exists.