Disparities in breast cancer treatment and outcomes: biological, social, and health system determinants and opportunities for research

Abstract

Racial disparities in breast cancer mortality have been widely documented for several decades and persist despite advances in receipt of mammography across racial groups. This persistence leads to questions about the roles of biological, social, and health system determinants of poor outcomes. Cancer outcomes are a function not only of innate biological factors but also of modifiable characteristics of individual behavior and decision making as well as characteristics of patient-health system interaction and the health system itself. Attempts to explain persistent racial disparities have mostly been limited to discussion of differences in insurance coverage, socioeconomic status, tumor stage at diagnosis, comorbidity, and molecular subtype of the tumor. This article summarizes existing literature exploring reasons for racial disparities in breast cancer mortality, with an emphasis on treatment disparities and opportunities for future research. Because breast cancer care requires a high degree of multidisciplinary team collaboration, ensuring that guideline recommended treatment (such as endocrine therapy for hormone receptor positive patients) is received by all racial/ethnic groups is critical and requires coordination across multiple providers and health care settings. Recognition that variation in cancer care quality may be correlated with race (and socioeconomic and health system factors) may assist policy makers in identifying strategies to more equally distribute clinical expertise and health infrastructure across multiple user populations.

Keywords: Access to care; Breast cancer; Cancer care quality; Disparities; Race.

Figure 1.

Breast cancer incidence and mortality by age at diagnosis and race/ethnicity. (A): Age-specific SEER female breast cancer incidence rates by race/ethnicity, all ages, 1992–2010. (B): Age-specific US female breast cancer mortality rates by race/ethnicity, all ages, 1992–2010 [16].

Figure 2.

Race-stratified Kaplan-Meier plots and race effect estimates for breast cancer-specific mortality by immunohistochemical subtype in the Carolina Breast Cancer Study, 1993–2006 [27]. Abbreviations: CI, confidence interval; ER, estrogen receptor; HR, hazard ratio.

Figure 3.

Age-adjusted U.S. female breast cancer-specific mortality rates by race, 1975–2005 [16].