Objective: To investigate the rate of objective response and the skeletal-related event (SRE)-free survival after combined therapy with radiotherapy (RT) and zoledronate in patients with bone metastases from renal cell carcinoma (RCC).
Patients and methods: In all, 23 patients with RCC metastatic to bone were included in this retrospective study, of whom 13 had RT to bone metastases with no bisphosphonate therapy between 2000 and 2006, while the remaining 10 had combined therapy with RT and zoledronate (RT + Z) in 2006 and 2007. Significant calcifications of osteolytic metastases and/or shrinkage of bone lesions, as measured by computed tomography, were defined as a partial response. SREs were defined as any of pathological fracture, spinal cord compression, bone surgery, or additional RT to the bone.
Results: In the RT + Z group, six patients had a partial response, showing evidence of calcification of their osteolytic bone metastases, while in the RT group, only one patient did (P = 0.019). One patient in the RT + Z group had an SRE, while 10 in the RT group had SREs (P = 0.003). The median SRE-free survival time was not reached in the RT + Z group, but in the RT group it was 18.7 months (P = 0.046).
Conclusion: Combined therapy as RT + Z achieved a higher objective response rate (six of 10) and prolonged SRE-free survival than RT alone in patients with bone metastases from RCC.