Outcomes of patients with metastatic renal cell carcinoma and bone metastases in the targeted-therapy era.

Abstract

528 Background: Bone metastases (BM) occur commonly in patients with metastatic renal cell carcinoma (mRCC). Tyrosine kinase inhibitors (TKIs) have improved outcomes for patients with mRCC. Data on outcomes of mRCC patients with BM treated with TKIs are limited, but suggest a worse outcome compared to non-BM groups. Herein, we describe outcomes of patients with BM treated with TKI therapy, and compare to outcomes in a pre-TKI control group. Methods: Retrospective review of patients with mRCC in the intervals of 2002-2003 and 2006-2007 was performed using the institutional tumor registry. Patient characteristics including demographics, laboratory data, and outcomes were analyzed. Overall survival (OS) was estimated using Kaplan-Meier methods. Predictors of OS were analyzed using Cox regression. Results: 375 patients were reviewed; 187 patients (50%) started treatment with TKIs and 188 patients (50%) started treatment in pre-TKI era. Distribution of patient characteristics was similar. Organ metastases were equally distributed, including BM in 48% of patients in each cohort. Median OS of patient treated with TKI therapy was 22 mo (95% CI: 17-25) compared to 14 mo (95% CI: 10-19; p<0.01) for historical controls. Subset analysis of patients with BM treated with TKI therapy demonstrated a median OS of 24 mo (95% CI: 17-28) compared to 18 mo (95% CI: 10-21; p<0.01), in non TKI treated group. Predictors of shorter OS were higher MSKCC score; liver, lung, and brain metastases; and multiple sites of BM (HR 1.38; 95% CI: 1.02-1.91; p=0.04). Rate of new BM development was the same in the pre-versus-post TKI era. Conclusions: Median survival of patients with BM appears to be slightly longer than the median, irrespective of systemic therapy received. Rate of BM development was the same in the pre-versus post-TKI era. The slightly prolonged OS with BM contradicts published data. The management of bone metastases in mRCC remains a challenge. [Table: see text]