Possible improvement of survival with use of zoledronic acid in patients with bone metastases from renal cell carcinoma

Abstract

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. 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. 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). The current study indicates that ZOL not only reduces SREs but possibly improves OS in these patients.