Positive effects of zoledronate on skeletal-related events in patients with renal cell cancer and bone metastases.

INTRODUCTION

Approximately 30% of patients with renal cell cancer (RCC) develop bone metastasis causing skeletal-related events (SRE): pathologic fracture, spinal cord compression, surgery to bone and radiotherapy. Zoledronic acid demonstrated significant clinical benefit in RCC patients in a retrospective analysis. Primary objective of this prospective study was the proportion of patients experiencing ≥ 1 SRE during 12 months of zoledronic acid treatment and to verify the retrospective data.

MATERIALS AND METHODS

Fifty patients with histologically confirmed RCC and evidence of ≥ 1 cancer-related bone lesion and ≤ 3 prior bisphosphonate applications were enrolled in 19 German centers between 2004 and 2007. The patients received 4 mg zoledronic acid every 3 weeks for 12 months followed by a follow up period for overall survival of 12 months. Bone lesions were diagnosed by bone scan or MRI-quickscan. Greater and equal to 1 lesion had to be confirmed by x-ray, CT or MRI scan. Additional bone scans were performed after completion of study treatment and if clinically indicated. In case of suspicion or evidence of a SRE it had to be confirmed radiologically.

RESULTS

In total, 49 of the 50 enrolled patients were treated. Only 11 of them (22.4%) experienced any SRE until month 12. Patients with > 6 lesions and higher baseline MSKCC (Memorial Sloan-Kettering Cancer Center) score had a higher risk for SREs. Zoledronic acid was generally well tolerated and its known safety profile was affirmed.

CONCLUSIONS

This prospective study confirms the results of prior data about the efficacy of zoledronic acid in patients with metastatic (m)RCC, supporting its beneficial use in these patients.