Breast cancer is the most common female malignancy in the United States and worldwide. The World Health Organization estimates that more than 1 million cases of breast cancer occur annually. In 2000, the last year in which worldwide data was available, more than 400,000 women died of breast cancer.1 Over the last several decades, a growing literature has described disparities in the incidence, treatment, and survival from breast cancer between populations delineated by socioeconomic, racial/ethnic, and cultural characteristics. Despite a growing recognition that disparities exist, the underlying causes of these disparities are not well understood. Factors affecting the incidence of and survival from breast cancer are no doubt multifactorial, including biological and genetic factors, environmental factors, reproductive factors, and dietary factors. Despite significant advances in the detection and treatment of breast cancer, these disparities have persisted. This review will focus primarily on disparities in breast cancer incidence, treatment, and outcome between African American and white women, as this represents the best established literature.
Evidence of the racial and socioeconomic differences in the incidence and mortality from breast cancer is compelling. The best population-based evidence of these disparities comes from the Surveillance, Epidemiology, and End Results (SEER) Program. This program was started in the United States in 1973 to describe the incidence and outcomes from cancers. Initially, 9 sites were involved, including 5 states (Connecticut, Hawaii, Iowa, New Mexico, and Utah) and 4 major cities (Detroit, Atlanta, San Francisco, and Seattle); however, the program has now grown to include 16 sites. In 2001, sites were added in Louisiana, Kentucky, New Jersey, and California to further improve the representation of minorities. This database now represents the largest collection of cancer registries in the United States. The SEER program is estimated to include 26% of the US population. SEER coverage includes 23% of African Americans, 40% of Hispanics, 42% of American Indians and Alaska Natives, 53% of Asians, and 70% of Hawaiian/Pacific Islanders.2 Although race is documented in the SEER database, the racial and ethnic heterogeneity of the US population presents a challenge to correctly accounting for these complex relationships. Despite this limitation, the SEER database has provided researchers and clinicians with robust population-based estimates of the cancer incidence and survival.
Disparities in Breast Cancer Epidemiology
The incidence of breast cancer has significant racial variation. Using the most recent SEER data, African American women have a lower age-adjusted incidence of breast cancer as compared with white women (117.5 vs 130.6 per 100,000 respectively) (Fig 102-1). Similarly, Asian/Pacific Islander, Hispanic, and American Indian/Alaskan Native women all have lower incidence of breast cancer as compared with white women (89.6, 90.1, and 75.0 per 100,000 women, respectively).2
The incidence of female breast cancer using SEER data (1975-2005). [Data from Ries LAG, Melbert D, Krapcho M, et al (eds). SEER Cancer Statistics ...