The finding that black Americans, compared with white Americans, have inferior 5-year survival rates and death rates from cancer has been noted for more than 40 years. Disparities in other causes of death were noted even earlier. Race and differences in health outcomes have been topics for politicians and scientists ever since.1 In many respects, the academic field of health outcomes research owes its creation to concerns about disparate outcomes among the races.
In America, race is a difficult, volatile topic. Medical science and the interpretation of data have been affected greatly by America's obsession with race. The finding that there are disparities in cancer incidence and mortality is incontrovertible.2 The reasons for the disparities and even how to define the populations with disparities are not as clear and, indeed, are quite controversial.
However populations are categorized, there are disparate influences on the cause of the disease. the course of the disease, and the outcome of the disease. Defining these influences is the most scientifically appropriate way to develop and test the interventions that may overcome these disparities.
Measuring Disparities in Health
Several demographic measures have been use to measure or demonstrate health disparities among 2 or more populations. These include:
Five-year survival rate
Stage distribution at diagnosis
Adequacy of treatment received
Quality of life.
Incidence rates, 5-year survival rates, and stage distribution are affected most by screening and early detection activities. Populations that have a higher prevalence of screening for a particular cancer frequently have a higher incidence of that cancer. A noted exception is colorectal screening, in which finding and removing benign polyps can decrease colorectal cancer incidence (prevent cancer).
The Demographic Data
Table 1 lists the incidence and mortality rates for the 15 most common cancers in the United States.3 The racial/ethnic categories are those mandated by the US Office of Management and Budget in 1998 and have been used by the US Census Bureau since 2000.
Table 1. Incidence and Mortality Rates by Sex 2001–2005*
AI indicates Pacific Islander; IBD, inflammatory bowel disease; NOS, not otherwise specified; ONS, other central nervous system.
Rates are per 100,000 population age adjusted to the year 2000 standard.
Adapted from: Ries LAG, Melbert D, Krapcho M, et al, eds. SEER Cancer Statistics Review, 1975–2005 (based on November 2007 SEER data submission, posted to the SEER website, 2008). Bethesda, Md: National Cancer Institute; 2007.3
Top 15 US cancer female mortality rates 2001–2005†
Lung and bronchus
Colon and rectum
Corpus and uterus, NOS
Brain and ONS
Liver and IBD
With few exceptions, Americans of black or African heritage have the highest mortality rates and the worst survival of any population.4 Some have suggested that genetic differences among the races are the cause of differences in mortality for breast, prostate, and colon cancer.5 The National Institutes of Health (NIH) Revitalization Act of 1993 mandates that all NIH-funded phase 3 clinical trials be designed to assess the differences in interventions between the races.6 The wording of the legislation actually attributes some if not most racial disparities on treatments, especially drugs, that have different affects on 1 race versus another.
Less emphasis has been placed on the possibility that environmental influences associated with being black affect the biology of cancer and cause worse prognoses. Even less emphasis is put on the finding that a lower proportion of blacks or African Americans receive high-quality medical care compared with white Americans. Racial disparities in quality of care received have been documented in the screening or prediagnostic setting as well as during treatment.
Most interest in disparities has centered on black-white differences. It is of concern that the incidence and mortality rates of some minority groups actually may be higher than reported because of coding discrepancies or lack of access to care, leading to a lack of diagnosis.7 Some populations, such as Native Americans, have such low cancer rates that it must asked whether the system is failing to count some Native-American cancer patients. The low cancer rates among Asians, Native Americans, and Hispanics, if they are accurate and are studied appropriately, have the potential to identify strategies that may be useful for blacks and whites. If these rates truly are low, then study of these populations may lead to preventive interventions for blacks and whites.
Although our labels and categories do predict for groups of individuals that are less likely to do well with cancer and other diseases, we must realize the sociopolitical nature of these categories. The concept of race is a remnant of the justification for slavery. The original categories date back several hundred years.8, 9 Negroid, Caucasoid, Mongoloid, and later derivations all are constructs rejected by anthropologists and based in societal politics. These categories are not based in science (taxonomy or anthropology).
It is noteworthy that the racial categories used in our country have changed over time. A man born in India in 1948 who immigrated to the United States before the 1950 Census would have been categorized into 3 different racial/ethnic groups by his 50th birthday. He would have been counted as Caucasian, Indian, and Asian.
It is truly unfortunate that data concerning health are collected using these sociopolitical categories and that scientific conclusions are drawn from them. The concept that phenotypic differences translate into biologic differences was the basis of ‘Race Medicine.’ This concept commonly was accepted in the 19th century and early 20th century America. It was talked about in numerous medical publications from the 1860s to the 1940s, and it was one of the reasons that the study commonly known as the ‘The Tuskegee Syphilis Study’ was deemed reasonable and ethical. It began in 1932 as a cohort study in which the affects of untreated syphilis were observed in Negro men, and it was deemed reasonable because it was believed that syphilis was a very different disease in blacks versus whites. Many actually believed that syphilis rarely killed Negroes but that it did kill whites.10 It is unfortunate today to read that breast cancer is a different disease in blacks versus whites or that prostate cancer is a different disease in blacks versus whites. This view can obscure the truth and actually can impede science from benefiting disparate populations.
Race is a sociopolitical categorization, and it can be a surrogate for other extrinsic causes of disease, such as socioeconomic status (SES) or culture. If we are truly to attack disparities in health outcomes, we must be open minded, question the standard paradigms, and carefully define the scientific and medical questions that need addressing.
Other more causally related and, thus, more scientific and more relevant ways of categorizing populations also can be used. These include ethnicity, SES, and area of geographic origin. All 3 can be correlated loosely with the sociopolitical concept of race within the United States. For example, the proportion of black Americans in poverty or near poverty in the United States is higher than the proportion of white Americans. For another example, ethnic Chinese (Asian Americans) are more likely to have a diet higher in vegetables compared with white Americans.
Ethnicity relates to a group of behaviors and habits, such as diet and other culturally related or environmental influences. Indeed, migration studies indicate that Asians who move to the United States from China and Japan and acculturate increase their risk of breast, prostate, and colon cancers, presumably through diet. Similar data have been reported regarding Eastern Europeans migrating from their homeland to Western Europe or Australia.11
Socioeconomic Status and Social Deprivation
In 2003, the US National Cancer Institute (NCI) published a monograph reporting that SES, which is influenced by education, income, and poverty level, is correlated with cancer outcomes. Americans living in poorer census tracts of the United States have inferior 5-year survival rates from most cancers. Individuals living in poorer areas also have higher incidence and higher mortality for most major cancers.12 American Cancer Society intramural epidemiologists have reported that lower education, lower SES, and lack of insurance are correlated with the greater likelihood of a poor outcome.13 Those with lower SES are more likely to present with higher stage disease; and, even within individuals who have the same disease stage, low SES is a predictor of worse outcome.
SES influences the quality and types of foods we eat, the environment in which we live, and the work that we do.14 It correlates with several environmental influences that can cause disease. The National Health Interview Survey suggests that poor Americans are more likely to have harmful health behaviors and are less likely to practice healthy behaviors. Compared with higher SES Americans, they consume higher calorie diets and have diets high in carbohydrates and fats. Poor Americans also are more likely to be overweight or obese and are less likely to consume diets high in fruits and vegetables compared with middle class and upper middle class Americans.15 Poor Americans may be more likely to live in neighborhoods with environmental pollutants, which may influence cancer, or in crime ridden neighborhoods, where exercise and recreation are not safe options.
Many of the factors that determine SES in the United States are related intimately to race. A higher proportion of Americans of African heritage are poor compared with whites. It is appropriate to ask about the affect poverty has on our race-based health statistics? Indeed, SES and its incumbent environmental influences may be the cause of many of our cancer disparities. It is possible that socioeconomic factors that act largely through and are associated with race are responsible for much of the disparity between blacks and whites.
The influence of social deprivation or SES and overall health also is observed in studies done in Scotland. Scotland is overwhelmingly Caucasian or white and has a very good health registry. At each decennial census, all Scots are categorized into 1 of 7 deprivation index categories. This index uses an extensive questionnaire to determine those who are the wealthiest (Category 1) and those who are the poorest or most deprived (Category 7). Figure 1 shows that the most deprived have a greater risk of death compared with the wealthiest or least deprived.16 Table 2 shows that the most affluent have better 5-year survival rates compared with the most deprived.16
Table 2. 5-Year Survival of Cancer Patients in Scotland by Affluence*
5-Year Survival, %
Adapted from: McLaren G, Bain M. Deprivation and Health in Scotland: Insights from NHS Data. Edinburgh: ISD Scotland, 1998.16
Scottish and American data reveal the influences that SES and social deprivation can have not only on the risk of malignant disease but also on pathologic factors.17, 18 The Europeans use the phrase ‘social deprivation’ in lieu of poverty. In population studies, they have demonstrated a correlation between social deprivation and the increase risk of having poor prognostic breast cancer biologies. Thomson and colleagues18 suggest that poor women with breast cancer are more likely to be diagnosed with estrogen receptor-negative tumors. In the middle 1990s, Gordon demonstrated similar findings when studying poor white women in Ohio. It is unknown how poverty influences the pathology of disease. This is likely through lifelong diet and birthing habits. Diets high in calories during childhood can affect menarche, which affects breast cancer risk later in life.
Area of Geographic Origin
Another way of categorizing populations is the area of geographic origin, which can correlate with ethnicity and race. The concept of area of geographic origin can be more scientific than race. It recognizes that someone may be of mixed origins, eg, both European and African origins or of indigenous American or Asian origins. In the United States, we often categorize an individual as black when their heritage is of several races or when they have various areas of geographic origin.
There are small genetic differences among populations as defined by area of geographic origin. Some of these differences have been associated with an environmental influence and/or a survival advantage. Sickle cell disease, for example, is associated with individuals from Spain, Italy, Greece, the Middle East, and northern and sub-Saharan Africa.19 It is noteworthy that, in the United States, sickle cell disease often thought of as a marker for Africans. Although the prevalence of sickle cell trait and sickle cell anemia is greater in sub-Saharan Africa, there is a prevalence among individuals who originate from southern Europe and who are considered white. Sickle cell is not observed among black Africans originating in southern Africa. It is believed that this genetic mutation is an example of genetic selection. Those who have sickle cell trait had some advantage during a massive malaria epidemic several thousand years ago. It is an example of environmental influences on genetics.
There are genetic markers that correspond with areas of geographic origin far better than with skin color or race. Glucose 6 phosphate dehydrogenase deficiency is common but not monopolized among individuals who originate in the Middle East and the Mediterranean.20 Alcohol dehydrogenase deficiency is another example: It is common in individuals from certain areas of Asia.21
There are populations often defined by other than racial criteria for whom certain drugs are less likely to work or are more likely to cause side affects. The epithelial growth factor inhibitor gefitinib (trade name, Iressa) clearly has greater activity in Japanese patients with nonsmall cell lung cancer as a group versus Americans of European ancestry.22 The drug irinotecan (trade name, Camptosar) may cause diarrhea in twice as many individuals who identify themselves as African in origin versus those who identify themselves as European in origin.23
Indeed, the scientific data suggest that pharmacogenomic differences among populations, however they are defined, are not the major reasons for disparities in health. These pharmacogenetic differences rarely mean that a particular drug should not be administered for a specific disease. The literature is filled with comparison studies demonstrating that there are racial differences in the amount and quality of care received. The major factor in health disparities is that a drug does not work because the poor, disenfranchised, or underserved patient does not get the drug.
Numerous patterns-of-care studies have been published that examine the black-white differences in healthcare. Unfortunately, few studies have studied disparities by SES, and very few have studied other racial/ethnic groups, such as Hispanics, Asians, or Native Americans.
Disparities in Lung Cancer
Irrespective of race, lung cancer mortality is strikingly higher in less educated men compared with men who have higher levels of education. Over the past 30 years, smoking rates have been higher among the less educated.
Data suggest that equal treatment yields equal outcomes among black and white patients with nonsmall cell lung cancer and small cell lung cancer.24 Surgical and radiation therapy outcomes all are similar.25, 26 Patterns-of-care studies indicate that black Americans less frequently receive surgical resection,24, 27–29 radiation therapy,24 chemotherapy,30 or any definitive treatment29 compared with whites.
In an article that received much press attention, Bach and colleagues noted that blacks with early-stage nonsmall cell lung cancer were less likely to receive curative resection compared with whites. It also was noted that blacks were more likely to die sooner than whites. In a population-based study of nearly 11,000 Medicare recipients with resectable nonsmall cell lung cancer (stage I and II) who were diagnosed between 1985 and 1993, 64% of blacks and 77% of whites underwent a resection. Blacks as a group have a 5-year survival rate of 26.4% versus 34.1% for whites. Among patients undergoing surgery, no racial difference was reported in survival.25
Disparities in Breast Cancer
The mortality rates for black and white Americans from 1975 to 2005 for breast cancer and colon cancer are provided in Figure 2. The major changes in the mortality rate over 3 decades probably are not attributable to differences in inherent genetic makeup of the populations. The growing disparity after a period of relative equivalence a more likely are because of differences in disease behavior brought on by differing changes in diet or, even more likely, differences in early detection and treatment received once patients are diagnosed.
In Scotland and in the United States, the poorest Americans tend to present with higher stage disease at diagnosis. Studies of Scots and Americans demonstrate that wealthier women with breast cancer are more likely to present with estrogen receptor-positive disease compared with poorer women, even within the same disease stage. A higher portion of poorer women are overweight or obese.17, 18 In a large study of Americans, breast cancer mortality rates were higher among women with less education than among women with more education. This finding was true regardless of race.13
Important questions that deserve more scientific resources include: ‘What is it about poverty that influences breast cancer tumor biology and the molecular markers of breast tumors?’ What are the environmental influences on tumor biology? The word ‘environmental’ has broad meaning and includes dietary influences and other chemical pollutants as well as reproductive habits.
We in medicine often do a sort of medical racial profiling to identify individuals who are at higher risk for a disease. A black American with breast cancer is more likely to have a triple-negative tumor, which means that the tumor is less likely to express estrogen receptors, progesterone receptors, and HER-2/neu.31 Most studies suggest that equal treatment yields equal outcomes among equal patients, and there is not equal treatment for many in the United States; this means that a black woman is less likely to receive optimal care in the United States compared with a white woman who has the same disease.
The study by Lund et al32 is eye-opening. Those authors assessed the care received by black and white women in a population-based Surveillance, Epidemiology, and Ends Results registry. Black women experienced longer treatment delays after diagnosis, regardless of their disease stage at diagnosis. Black women were 4- to 5-fold more likely to experience delays in treatment >60 days after diagnosis. For locoregional disease, significantly more black women did not undergo cancer-directed surgery (7.5% vs 1.5% of white women). Among patients who were eligible for breast-conserving surgery, only 61% of blacks versus 72% of whites received radiation. Among women who should have received hormone therapy, black women were less likely to receive it.32 Griggs et al33 found evidence that some chemotherapy drugs are given in lower than recommended doses because of obesity. In the United States, blacks have a higher prevalence of obesity than whites.
Disparities in Prostate Cancer
American men of African heritage have a higher incidence and mortality from prostate cancer compared with white men. Many have speculated there may be a genetic mutation, series of mutations, or polymorphisms common in men of African heritage that could cause the disparity. Epidemiologists have examined racial differences in CAG DNA repeat length and variations in polymorphisms of the CYP17 gene and the insulin growth factor 1 gene. All current data are inconclusive.34 Amundadottir and colleagues35 recently reported that 13% of men of European ancestry and 30% of black American men carry at least 1 variant of allele −8 of the microsatellite DG8S737 on chromosome 8q24, which confers an odds ratio of 1.62 for prostate cancer.
The various prostate cancer incidence rates in several populations of African origin (Table 3) suggest that some environmental influences do influence prostate cancer incidence rates among men of African origin.36 It should be noted that the black population in the United States is among the only of these groups in which screening is common. Screening for prostate cancer began in the United States early in the 1990s, and the screening rates appear to have increased among black Americans by approximately 30%. Even allowing for screening, the incidence rates of prostate cancer in black Americans are higher than those reported in other African populations.
Table 3. Prostate Cancer Incidence in 6 Populations of African Origin*
Adapted from: Parkin DM, Whelan SL, Ferlay J, Storm H. Cancer in Five Continents, 7th ed. Lyon, France: IARC, 2005.36
Age-adjusted to world standard.
Black, United States
Disparities in body mass index (BMI) and obesity may be the driving force in prostate cancer and in many black-white cancer disparities.37, 38 Black Americans tend to have higher BMI than white Americans. A higher proportion of Americans of African heritage have the metabolic syndrome and diabetes. This is a disease in which the levels of circulating insulin and insulin-like growth factors are elevated. The role that these increased levels of circulating growth factors have on prostate cancer and other cancer risks is unknown but of interest. Diet, for instance, is believed to play an important role in the differing prevalence of the metabolic syndrome, diabetes, and breast cancer pathologies.39
The American Cancer Society Cancer Prevention Study II Nutrition Cohort is a study of approximately 65,000 men who completed an initial questionnaire in 1992/1993 and were followed through 2001. Rodriguez et al40 reported that, among black men, total red meat intake, including processed and unprocessed meat, was associated with a higher risk of prostate cancer with a statistically significant 2-fold increase in relative risk. The influence of cooked processed meats was especially prominent with a relative risk of 2.7 comparing the highest quartile versus the lowest quartile Other, smaller studies also have observed that the consumption of cooked processed meats may contribute to prostate cancer in black men in the United States. This is an environmental influence associated with ethnicity and culture.
There appears to be a correlation between BMI, tumor characteristics, and treatment failure in prostate cancer. Spangler et al studied 924 patients (140 black men and 784 white men) and demonstrated that obese men (BMI >30 kg/m2) tended to have worse preoperative and postoperative tumor characteristics and biochemical relapse-free survival compared with nonobese men.41 Black American men tend to have higher BMI than age-matched white Americans. The direct affect on pathology that is associated with obesity is unknown. It is likely a factor associated with diet and calorie balance.
The poor and those with lower literacy tend to present with more advance disease. In several studies of American men with prostate cancer, literacy was correlated with advanced-stage disease, and race was not!42–44 Du et al45 observed that SES was a major barrier in achieving comparable outcomes for men with prostate cancer. Their is one of the few population-based studies that included a large number of Hispanic patients in addition to blacks and whites. Again, those authors observed that the influence of race and ethnicity was not nearly as powerful as the influence of SES.
Prostate cancer is another disease in which there appears to be some racial differences in patterns of care received. In the NCI-sponsored Prostate Cancer Outcomes Study, black men with high-grade disease tended to receive less aggressive therapy compared with white men with the same disease. There were no racial differences in the care of lower grade tumors.46 Others have demonstrated significant black-white differences in treatment.
Disparities in Colon Cancer
Large population-based studies and national surveys have demonstrated differences in patterns of colorectal cancer treatment by race/ethnicity. There is a consistent pattern of blacks tending to get less aggressive treatment than whites. This includes studies that assessed surgery47–51 and studies that assessed adjuvant therapy.52–54 In a meta-analysis of studies on black-white disparities in survival that focused on colon cancer, differences were only marginally significant after adjusting for socioeconomic factors and treatment.55
Disparities in Cervical Cancer
The mortality rate from cancer of the uterine cervix is small, but most of these deaths are avoidable through early detection and appropriate treatment. The incidence and mortality rate is highest among the less educated and most impoverished. There is a difference in quality of screening and quality of follow-up of abnormal findings among poor Americans compared with the middle class. There are several articles on population-based patterns of care in the literature. Studies also have reported racial/ethnic disparities in the receipt of treatment for cervical cancer. There are differences in the quality of clinical staging and differences in the proportions receiving definitive treatment (surgery or radiation). Blacks are more likely than whites to receive no treatment after diagnosis.56–58
Access to Quality Care
A major theme of this report is that disparities by race, area of geographic origin, and SES do exist. Many of the disparities are related to disparities or inequities in pattern of care among the poor and especially among black Americans. There are differences in preventive services as well as differences in treatment once patients are diagnosed. It is an unsettling truth that, as a society, we have made meager efforts toward solving this problem. Although healthcare disparities are a civil rights issue, adequate healthcare is a human right.
Many false beliefs and superstitions surrounding the biology of race have impeded our ability to deal with all aspects of the disparities issue. So often, our discomfort in dealing with racial matters obscures our ability to see the truth. A large body of literature now exists to demonstrate that the poor, including blacks, whites, and individuals of other races, are less likely to receive optimal care. In landmark studies, Bach and colleagues59 have catalogued the literature, disease by disease, to demonstrate that the literature almost always supports the concept that equal treatment produces equal outcomes in the treatment of cancer, and Shavers and Brown60 detailed data demonstrating that a larger proportion of minority and poor patients receive less than optimal care compared with nonminority patients. In plain language, there is not equal treatment.
By using Medicare claims data for treatment of colorectal, breast, lung, or prostate cancers during the period from 1990 to 2002, Gross and colleagues61 observed that black patients were significantly less likely than white patients to receive therapy for cancers of the lung (surgical resection for early-stage disease: 64% vs 78.5% for blacks and whites, respectively), breast (radiation after lumpectomy: 77.8% vs 85.8%), colon (adjuvant therapy for stage III disease: 52.1% vs 64.1%), and prostate (definitive therapy for early-stage disease: 72.4% vs 77.2%). There was little or no improvement over the 12 years in the proportion of patients receiving therapy for the cancers studied, and there was no decrease in the magnitude of any of the racial disparities. These patients all had Medicare coverage. The results from that study suggest that SES and insurance status are not the only reasons for the disparities in quality of care.
Access to care is a real problem in the United States. It is only 1 element in the problem of disparities in health. Of 285 million Americans, 35 million (12%) are poor, and 47 million have no health insurance. The number of Americans who have inadequate health insurance is even greater than the number of uninsured. Of Americans living without health insurance, they include 20% of all blacks, 32% of all Hispanics, and 11% of all whites. The absolute number of whites without health insurance is greater than the numbers of uninsured blacks and Hispanic combined. We might be able to persuade more Americans to support efforts to eliminate health disparities if those we defined those disparities in socioeconomic terms rather than racial terms.
The Health Disparities Research Agenda
Future disparities research should be aimed at identifying major social, environmental, healthcare, behavioral, and biologic determinants underlying these cancer disparities. The most important question in health disparities research is, ‘How can we provide adequate, high-quality care (to include preventive care) to a population that so often does not receive it?’ We must look beyond race/ethnicity to define that population. The number of poor whites receiving less than optimal care is greater than the number of blacks and Hispanics combined who receive less than optimal care. Physicians and healthcare providers also must ask whether they are asking the right scientific questions and whether questions about race are allowing them to ignore other, legitimate questions.
There are many other scientific questions to be addressed. They involve determining the elements of poverty or social deprivation that influence the experience of the cancer patient. These elements may be impeding good screening and early detection. They may hinder the patient from seeking optimal care or the caregiver from offering optimal care.
What is the influence of poverty or social deprivation on cancer biology?
Why are the poor at higher risk?
Why do the poor have the more aggressive pathologies?
What is the role of diet and cancer among these populations?
What unexplored environmental influences merit exploring?
There are patient-related factors that can cause lack of optimal care. Some care is not given because the patient refuses reasonable treatment or because social circumstances, such as lack of transportation, will not allow it. Some care may be withheld reasonably because of the increased presence of comorbid diseases, such as diabetes, hypertension.
Rational health promotion and advocacy of behavioral change is imperative if we are to reduce disparities. Beyond race, we as healthcare providers must realize that poverty and unfortunate circumstance drive many in the human race to receive less than optimal care and to incorporate unhealthy habits. So often, scientists have obsessed about biologic differences among racial groups and have not focused on the question, ‘How do we provide adequate care to include preventive care and education to those who so often do not receive it?’ These are academic issues for nurse and physician healthcare providers as well as social workers, economists, and others.