Effect of race on survival of metastatic renal cell carcinoma treated with VEGFR-TKI therapy.

Abstract

e15507 Background: African Americans (AAs) with renal cell carcinoma (RCC) have a higher incidence of disease, younger age of onset, and at least in the cytokine era AA have had a shorter progression free survival (PFS) and overall survival (OS) relative to Caucasians (Cs). Vascular Endothelial Growth Factor Receptor Tyrosine Kinase Inhibitors (VEGFR-TKIs) were approved for advanced RCC based on trials with minimal AA participation. This study was undertaken to examine if VEGFR-TKIs are similarly effective in AA patients. Methods: This was a single institution retrospective cohort study. We examined the medical records from 2004 to 2012 of all C and AA patients with metastatic RCC started on first line VEGFR-TKI therapy with at least one follow up visit. This resulted in 34 C patients and 12 AA patients. We abstracted self- reported race, treatment type, MSKCC prognosis, date of progression as defined by the treating physician, and other demographic and clinical variables. The Social Security Death Index was used to establish date of death. OS and PFS were analyzed using Kaplan-Meier and Cox proportional hazards models. Gene expression data from TCGA was analyzed for biological differences between RCC occurring in AAs and Cs. Results: 54.6% of AAs were classified into the MSKCC poor prognosis group compared with 10.7% of Cs. AAs compared to Cs had a non-significant trend toward worse OS (HR 1.49, p = 0.36) and PFS (HR 1.59, p = 0.27). After adjustment for risk group we found no significant difference between AAs and Cs for OS (HR 1.00, p = 0.99) and PFS (HR 1.26, p = 0.66). Comparison of the RCC gene expression profiles demonstrated significant differences in gene expression with AA tumors showing enrichment for genes involved in ion transport and cell-cell junctions. Conclusions: This is a preliminary study that suggests first line VEGFR-TKI therapy is an effective choice for AA patients as metastatic RCC in AAs responds similarly as Cs to VEGFR-TKI treatment. In addition, there are distinct gene expression differences that distinguish AA and C tumors.