Outcomes of Patients With Metastatic Renal Cell Carcinoma and Bone Metastases in the Targeted Therapy Era

Bone metastases (BMs) are frequently seen in patients with metastatic renal cell carcinoma. Tyrosine kinase inhibitors (TKIs) have improved the overall outcomes. However, data on their effect in patients with BMs seems to be limited. In the present study, we describe the outcomes of patients with BMs treated with TKI therapy and compare them with the outcomes from pre-TKI group. Our study showed that the incidence of BMs was the same in the pre- and post-TKI era. Background Bone metastases (BMs) occur commonly in patients with metastatic renal cell carcinoma (mRCC). Tyrosine kinase inhibitors (TKIs) have improved the outcomes for patients with mRCC. However, data on the outcomes of mRCC patients with BMs treated with TKIs are limited. We describe the outcomes of patients with BMs treated with TKI therapy and compare them with the outcomes from a pre-TKI group. Patients and Methods Using an institutional tumor registry, a retrospective review of patients with mRCC from 2002 to 2003 and 2006 to 2007 was performed. The baseline characteristics were analyzed, and overall survival (OS) was estimated using the Kaplan-Meier method. The predictors of OS were analyzed using Cox regression analysis. Results The data from 375 patients were reviewed. Of these patients, 188 (50%) started treatment with TKIs and 187 (50%) had started treatment in the pre-TKI era. The distribution of patient characteristics was similar. The sites of organ metastases were equally distributed, including BMs in 48% of the patients in each cohort. The median OS for the patients treated in the TKI era was 22 months (95% confidence interval [CI], 17-25 months) compared with 14 months (95% CI, 10-19 months; P < .01) for the historical controls. A subset analysis of patients with BM in the TKI era demonstrated a median OS of 24 months (95% CI, 17-28 months) compared with 18 months (95% CI, 10-21 months; P < .01) in pre-TKI era. The predictors of shorter OS were a higher Memorial Sloan Kettering Cancer Center score; liver, lung, and brain metastases; and multiple sites of BMs (hazard ratio, 1.38; 95% CI, 1.02-1.91; P = .04). The rate of new BM development was the same in the pre- and post-TKI era. Conclusion The rate of BM development was the same in the pre- and post-TKI era. The management of BMs in patients with mRCC remains challenging.