A population-based study examining the effect of tyrosine kinase inhibitors on survival in metastatic renal cell carcinoma in Alberta and the role of nephrectomy prior to treatment

Abstract

BACKGROUND: We performed a retrospective population-based study to assess the impact of tyrosine kinase inhibitors (TKIs) on overall survival (OS) in patients treated for metastatic renal cell carcinoma (mRCC) in Alberta, Canada and to assess the impact of nephrectomy on OS in patients treated with TKIs. METHODS: We identified 134 patients who began taking a TKI between December 2003 and June 2007 for mRCC in Alberta. We compared survival in this group to that in an earlier cohort of 141 patients treated with interferon-alpha (IFN-alpha) between May 1995 and March 2003. We used the Kaplan-Meier method to determine OS, and we used a Cox proportional hazards model to determine hazard ratios (HRs) and confidence intervals (CIs). We performed multivariate analysis to assess the impact of neprhectomy on OS. RESULTS: Of the 134 patients treated with TKIs, 81 received treatment in the first-line setting, whereas 53 received treatment after prior IFN-alpha therapy. All 141 patients from the IFN-alpha cohort received treatment in the first-line setting. Patients treated with TKIs had an improved OS compared with the IFN-alpha cohort (HR 0.61, 95% CI 0.45-0.83, p = 0.001). The median OS was 18 months in the TKI group and 10 months in the IFN-alpha group. The benefit of TKIs was confined to favourable and intermediate risk groups according to the Memorial Sloan-Kettering Cancer Center prognostic model. Prior nephrectomy was associated with improved OS in the TKI cohort, independent of other prognostic factors. CONCLUSION: Tyrosine kinase inhibitors improve OS compared with IFN-alpha in mRCC. In patients treated with TKIs, prior nephrectomy is associated with improved survival independent of other prognostic variables.