Background: Bisphosphonates play an indisputable role in preventing skeletal-related events (SREs) secondary to bone metastases, and also have a direct effect on tumor cells. However, it remains unclear whether bisphosphonates improve overall survival (OS) for renal cell carcinoma (RCC) patients with bone metastases.
Methods: Between 1978 and 2010, a total of 45 patients who had RCC metastatic to bone and were classified as intermediate risk according to Memorial Sloan-Kettering Cancer Center criteria were included in this retrospective study. In this cohort, 23 patients received zoledronic acid (ZOL) treatment (ZOL-treated group) whereas the other 22 did not (non-ZOL-treated group). The primary endpoint was OS and the secondary endpoint was the SRE rate defined as the total number of SREs divided by the total years under study.
Results: For the cohort of 45 patients, the median OS from diagnosis of bone metastases was 27.2 months. Multivariate analysis showed that lower serum calcium (p = 0.0083) and ZOL treatment (p = 0.0013) were independent factors predicting longer survival. The ZOL-treated group had significantly longer OS than the non-ZOL-treated group (p = 0.0034). Patients in the ZOL-treated group experienced a lower SRE rate than patients in the non-ZOL-treated group (p = 0.0453). In particular, none of the patients in the ZOL-treated group developed spinal compression whereas 6 (28%) in the non-ZOL-treated group did (p = 0.0479).
Conclusions: The current study indicates that ZOL not only reduces SREs but possibly improves OS in these patients.