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.
Dr. Royce is a member of the advisory board for Genentech and a member of the speakers bureau for Novartis.
1. US Census Bureau: Race and Hispanic origin in 2004. Available at www.census.gov. Accessed August 14, 2006.
2. US Census Bureau: Asian origin: National population estimates by age, race and Hispanic origin, 2003. Available at www.census.gov. Accessed August 14, 2006.
3. Centers for Disease Control: United States Cancer Statistics: 2002 Incidence and Mortality. Available at www.cdc.gov/cancer/npcr/uscs/pdf/2002_USCS.pdf. Accessed August 14, 2006.
4. Jemal A, Siegel R, Ward E, et al: Cancer statistics, 2006. CA Cancer J Clin 56:106-130, 2006.
5. US Department of Health and Human Services: Healthy People 2010. Available at www.healthypeople.gov. Accessed August 14, 2006.
6. Li CI, Malne KE, Daling JR: Differences in breast cancer stage, treatment, and survival by race and ethnicity. Arch Intern Med 163:49-56, 2003.
7. New Mexico Cancer Facts & Figures 2005-2006. In press.
8. Chu KC, Lamar CA, Freeman HP: Racial disparities in breast carcinoma survival rates: Separating factors that affect diagnosis from factors that affect treatment. Cancer 97:2853-2860, 2003.
9. Joslyn SA: Racial differences in treatment and survival from early-stage breast carcinoma. Cancer 97:1759-1766, 2002.
10. American Cancer Society: Cancer Facts and Figures 2004. Atlanta, American Cancer Society, 2004.
11. Agency for Healthcare Research and Quality, US Department of Health and Human Services. National Healthcare Disparities Report, 2005. Available at http://www.ahrq.gov/qual/nhdr05. Accessed August 14, 2006.
12. Hershman D, McBride R, Jacobson JS, et al: Racial disparities in treatment and survival among women with early-stage breast cancer. J Clin Oncol 23:6639-6646, 2005
13. Gwyn K, Bondy ML, Cohen DS, et al: Racial differences in diagnosis, treatment, and clinical delays in population-based study of patients with newly diagnosed breast carcinoma. Cancer 100:1595-1604, 2001.
14. Lannin DR, Matthews HF, Mitchell J, et al: Influence of socioeconomic and cultural factors on racial differences in late-stage presentation of breast cancer. JAMA 279:1801-1807, 1998.
15. Miller BA, Hankey BF, Thomas TL: Impact of sociodemographic factors, hormone receptor status, and tumor grade on ethnic differences in tumor stage and size for breast cancer in US women. Am J Epidemiol 155:534-545, 2002.
16. Rao RS, Graubard BI, Breen N, et al: Understanding factors underlying discrepancies in cancer screening using the Peters-Belson approach. Med Care 42:789-800, 2004.
17. Blanchard K, Colbert JA, Puri D, et al: Mammographic screening: Patterns of use and estimated impact on breast carcinoma survival. Cancer 101:495-507, 2004.
18. Du W, Simon MS: Racial disparities in treatment and survival of women with stage I-III breast cancer at a large academic medical center in metropolitan Detroit. Breast Cancer Res Treat 91:243-248, 2005.
19. Saha S, Taggart SH, Komaromy M, et al: Do patients choose physicians of their own race? Health Aff 19:76-83, 2000.
20. Bakemeier RJ, Krebs LU, Murphy JR, et al: Attitudes of Colorado health professionals toward breast and cervical cancer screening in Hispanic women. J Natl Cancer Inst Monograph 18:95-110, 1995.
21. Frank-Stromborg M, Wassner LJ, Nelson M, et al: A study of rural Latino women seeking cancer-detection examinations. J Cancer Educ 13:231-241, 1998.
22. Suarez L, Nichols DC, Pulley L, et al: Local health departments implement a theory-based model to increase breast and cervical cancer screening. Public Health Reports 108:477-482, 1993.
23. Hubbell FA, Chavez LR, Mishra SI, et al: Differing beliefs about breast cancer among Latinas and Anglo women. Western J Med 164:405-409, 1996.
24. Chavez LR, Hubbell FE, Mishra Se, et al: The influence of fatalism on self-reported use of Papnicolaou smears. Am J Preventive Med 28:418-425, 1999.
25. Balcazar H, Castro FG, Krull JL: Cancer risk reduction in Mexican American women: The role of acculturation, education, and health risk factors. Health Educ Quarterly 22:61-84, 1995.
26. Leybas-Amedia V, Nuno T, Garcia F: Effect of acculturation and income on Hispanic women's health. J Health Care Poor Underserved 16:128-141, 2005.
27. Giarratano G, Bustamante-Forest R, Carter C: A multicultural and multilingual outreach program for cervical and breast cancer screening. J Obstet Gynecol Neonatal Nurs 34:395-402, 2005.
28. Gansler T, Jenley SJ, Stein K, et al: Sociodemographic determinants of cancer treatment health literacy. Cancer 104:653-660, 2005.
29. Denberg TD, Wong S, Beattie A: Women's misconceptions about cancer screening: Implications for informed decision-making. Patient Education and Counseling 57:280-285, 2005.
30. Tammemagi CM, Nerenz D, Neslund-Dudas C, et al: Comribidity and survival disparities among black and white patients with breast cancer. JAMA 294:1765-1772, 2005.
31. National Diabetes Education Program, National Institutes of Health: The diabetes epidemic among Hispanic and Latino Americans. Available at http://ndep.nih.gov/diabetes/pubs/FS_HispLatino_Eng.pdf. Accessed August 14, 2006.
32. Smith K, Wray l, Klein-Cabral M, et al: Ethnic disparities in adjuvant chemotherapy for breast cancer are not caused by excess toxicity in black patients. Clin Breast Cancer 6:260-266, 2005.
33. Boyd NF, Byng JW, Jong RA, et al: Quantitative classification of mammographic densities and breast cancer risk: Results from the Canadian National Breast Screening Study. J Natl Cancer Inst 87:670-675, 1995.
34. Byrne C, Schairer C, Wolfe J, et al: Mammographic features and breast cancer risk: Effects with time, age, and menopause status. J Natl Cancer Inst 87:1622-1629, 1995.
35. Kerlikowske K, Creasman J, Leung J, et al: Differences in screening mammography outcomes among with, Chinese and Filipino women. Arch Intern Med 165;1862-1868, 2005.
36. Gail MH, Brinton LA, Byar DP, et al: Projecting individualized probabilities of developing breast cancer for white females who are being examined annually. J Natl Cancer Inst 81:1897-1886, 1989.
37. Chlebowski RT, Chen Z, Anderson GL, et al: Ethnicity and breast cancer: Factors influencing differences in incidence and outcome. J Natl Cancer Inst 97:439-448, 2005.
38. McCaskill-Stevens W, McKinney MM, Whitman CG, et al: Increasing minority participation in cancer clinical trials: The minority-based community clinical oncology program experience. J Clin Oncol 23:5274-5254, 2005.