Meta-analysis of survival in African American and white American patients with breast cancer: Ethnicity compared with socioeconomic status

Purpose: The extent to which socioeconomic disadvantages and inadequate health care access account for the disproportionately elevated mortality hazard observed in African American compared with white American patients with breast cancer is poorly defined. Methods: We identified 20 studies reported between January 1980 and June 2005 that provided survival analyses in patients with breast cancer after adjusting for ethnicity and some measurement of socioeconomic status. These studies also adjusted for age and stage of disease at time of diagnosis. Results: The pooled outcome data yielded estimates for the mortality hazard in 14,013 African American and 76,111 white American patients with breast cancer. Studies varied in their methods for assigning socioeconomic status, with most relying on area-wide measures such as census tract and census block data. The combined analysis (adjusted for age, stage, and socioeconomic status) revealed that African American ethnicity was associated with a statistically significant excess mortality risk in overall survival (mortality hazard, 1.27; 95% CI, 1.18 to 1.38) and in breast cancer-specific survival (mortality hazard, 1.19; 95% CI, 1.10 to 1.29). Conclusion: Our pooled analysis demonstrated that African American ethnicity is a significant and independent predictor of poor outcome from breast cancer, even after accounting for socioeconomic status by conventional measures. These findings support the need for further investigation of the biologic, genetic, and sociocultural factors that may influence survival in African American patients with breast cancer.