Racial and ethnic diversity is increasing and shifting rapidly in the US population, resulting in unique challenges to the health-care system. As of 2004, Hispanics were the largest minority group, representing approximately 14% (41.3 million) of the total US population. Other groups are increasing in size as well. For example, Asians are increasing at triple the rate of the US population.
Cancer has an impact on racial and ethnic minorities in distinctive ways. For men, African-Americans have the highest cancer incidence and mortality, followed by whites and Hispanics. For women, whites have the highest incidence, but African-Americans have the highest mortality, followed by whites, Native Americans/Alaskan Natives, and Hispanics.[3,4] Disparities between incidence and mortality rates become apparent when details, such as the use of screening/prevention strategies and stage of diagnosis, are considered.
The government has made addressing health-care disparities a priority through the Healthy People 2010 initiative. One of the program goals is the complete elimination of disparities in health care. Accomplishing this goal requires an understanding of existing racial and ethnic disparities. This review begins to unravel some of the causes underlying racial/ethnic discrepancies in cancer care. In order to provide a context for discussion of a broad and diverse topic, this review will highlight breast cancer as a prototype.
Disparities in Cancer Incidence and Survival
The Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute (NCI) reports substantially lower age-adjusted breast cancer rates for minority women. The incidence rate for white women is 141.1 cases per 100,000, 119.4 for African-Americans, 96.6 for Asian/Pacific Islanders, 89.9 for Hispanics, and 54.8 for American Indians/Alaskan Natives. However, these statistics do not tell the full story of lower screening rates, advanced-stage diagnosis, and increased mortality among these racial/ethnic groups. Differences in mortality between non-Hispanic white women and minorities are most dramatic for African-Americans, whose mortality rate is 34.7 per 100,000 across all age groups. For white women, the mortality rate is 25.9 per 100,000, despite the higher incidence.
Evaluation of SEER data also revealed a 60% increased risk of a stage IV diagnosis in white Hispanic women of South/Central American origin. This risk increased dramatically to 260% for Puerto Rican women. Although Hispanic women faced an increased mortality rate, further analysis suggests regional differences. In New Mexico, which has a large Hispanic population, breast cancer mortality rates have remained relatively stable at approximately 20% of incidence (personal communication, New Mexico Tumor Registry).
What factors account for disparities in breast cancer outcome? Several studies have shown that African-American and Hispanic women tend to be diagnosed with more advanced-stage cancers and are less likely to receive standard of care in a timely manner.[6,8,9] Use of mammography has led to earlier stage at diagnosis, and less frequent use may partly explain the more advanced stage at diagnosis, where chance for cure is reduced. According to the American Cancer Society (ACS), 72.1% of non-Hispanic white women over the age of 40 had received a mammogram in the past 2 years. This rate declines to 68.2% for African-Americans, 62.6% for Hispanics/Latinos, 57.0% for Asian-Americans, and 52.0% for American Indians/Alaskan Natives.
Since ethnic minorities are disproportionately of lower socioeconomic status, the 2005 National Health Disparities Report (NHDR) stratified screening mammography by income and education level to distinguish the effects of race/ethnicity and socio-economic status. Interestingly, after controlling for income, African Americans and Hispanics in the lower income groups were more likely to receive mammography than their white and non-Hispanic white counterparts, respectively. Furthermore, after controlling for education, black high school graduates were more likely to receive mammography than white high school graduates.
Failure to receive standard of care in a timely manner or to complete recommended therapy may also account for some of the outcome disparities. In a study by Hershman et al, those who halted treatment early were more likely to die than those who completed treatment. Approximately 31% of African-American women with breast cancer stopped treatment prematurely, and African-American women were more than twice as likely to die from breast cancer as white women (of whom only 23% did not complete therapy). In this study, all the women had health insurance, so continued access to care is less likely to be a deterrent for completing therapy. The reasons for disparity in treatment completion among the racial groups in this study were not elaborated on, but the authors plan to investigate this issue. Other studies corroborate this trend of decrease in treatment among racial/ethnic minority groups when adjusted for socioeconomic status and access to care.