Exploring racial differences in outcome and treatment for metastatic colorectal cancer

BACKGROUND: African Americans are more likely to be diagnosed with metastatic colorectal cancer than whites and have shorter survival once they are diagnosed. In this analysis, the authors examined racial differences in clinical outcomes among patients with metastatic colorectal cancer (mCRC) who received bevacizumab. METHODS: The study cohort consisted of 1589 white patients (81.4%) and 227 African American patients (11.6%) with mCRC who received front-line bevacizumab therapy and who were enrolled in a large, predominantly community-based, prospective, observational cohort study. Differences in time-to-event endpoints and response rates were examined by race. Differences in the incidence of baseline and treatment-related toxicities associated with bevacizumab also were examined. Finally, differences in patterns of care by race were explored. RESULTS: The median overall survival was 22.6 months for African Americans and 22.9 months for whites, and the median progression-free survival was 9.5 months for African Americans and 9.8 months for whites. Response rates (complete responses plus partial responses) were 37.5% for African Americans and 46.3% for whites (adjusted odds ratio, 0.67; 95% confidence interval, 0.50-0.90). African Americans had higher rates of baseline diabetes (18.9% vs 11%; P = .002), higher rates of hypertension (52.9% vs 41.4%; P = .001), and worsening hypertension while on therapy (13.7% vs 8.9%; P = .02), but no differences in on-treatment arterial thromboembolic events were observed. CONCLUSIONS: This large observational cohort study of patients with mCRC demonstrated that, when treated in a similar fashion with modern chemotherapy, African Americans and whites had equivalent cancer outcomes. No significant differences in bevacizumab-related toxicity or patterns of care were observed between African Americans and whites. The lower response rate among African Americans deserves further study. Cancer 2012;118:1083-90. (C) 2011 American Cancer Society.