Renal cell carcinoma (RCC) is thought to respond unreliably to radiotherapy (RT). Zoledronic acid significantly reduces the risk of skeletal complications. This study investigated whether RT with zoledronic acid prolonged the time to bone-lesion progression in comparison with RT alone.
Twenty-seven patients (34 lesions) with bone metastases secondary to RCC undergoing treatment with RT with or without zoledronic acid were retrospectively evaluated at two institutions between 1999 and 2009. Twelve patients were treated with RT alone from 1999 to 2008 (RT group). Fifteen patients were treated with RT and zoledronic acid from 2006 to 2009 (RT + Z group). The time to skeletal-related events and pain progression were assessed from patients' medical records.
The median (range) follow-up was 26 (3-75) and 24 (3-55) months in the RT and RT + Z groups, respectively. Three patients (three lesions) in the RT + Z group had skeletal-related events (SREs). In contrast, six patients (eight lesions) in the RT group had SREs. SREs comprised pathological fractures in five, additional surgeries in three, spinal cord or cauda equine compression in two, and repeat RT in one. There was a significant difference in SRE-free survival time and duration of site-specific pain response between groups.
RT combined with zoledronic acid significantly prolonged SRE-free survival and duration of pain response compared with RT alone in the treatment of osseous metastases from RCC.