Cancer Health Disparities
How does the National Cancer Institute (NCI) define “cancer health disparities”?
The National Cancer Institute (NCI) defines “cancer health disparities” as adverse differences in cancer incidence (new cases), cancer prevalence (all existing cases), cancer death (mortality), cancer survivorship, and burden of cancer or related health conditions that exist among specific population groups in the United States. These population groups may be characterized by age, disability, education, ethnicity, gender, geographic location, income, or race. People who are poor, lack health insurance, and are medically underserved (have limited or no access to effective health care) – regardless of ethnic and racial background – often bear a greater burden of disease than the general population.
A close look at cancer incidence and death statistics reveals that certain groups in this country suffer disproportionately from cancer and its associated effects, including premature death. For example, African Americans/Blacks, Asian Americans, Hispanic/Latinos, American Indians, Alaska Natives, and underserved Whites are more likely than the general population to have higher incidence and death statistics for certain types of cancer.
What factors contribute to cancer health disparities?
Complex and interrelated factors contribute to the observed disparities in cancer incidence and death among racial, ethnic, and underserved groups. The most obvious factors are associated with a lack of health care coverage and low socioeconomic status (SES).
SES is most often based on a person’s income, education level, occupation, and other factors, such as social status in the community and where he or she lives. Studies have found that SES, more than race or ethnicity, predicts the likelihood of an individual’s or a group’s access to education, certain occupations, health insurance, and living conditions. including conditions where exposure to environmental toxins is most common. all of which are associated with the risk of developing and surviving cancer. SES, in particular, appears to play a major role in influencing the prevalence of behavioral risk factors for cancer (for example,tobacco smoking, physical inactivity, obesity, excessive alcohol intake, and health status), as well as in following cancer screening recommendations.
Research also shows that individuals from medically underserved populations are more likely to be diagnosed with late-stage diseases that might have been treated more effectively or cured if diagnosed earlier. Financial, physical, and cultural beliefs are also barriers that prevent individuals or groups from obtaining effective health care.
How does NCI gather data on cancer incidence and death for various population groups in the United States?
The Surveillance, Epidemiology, and End Results (SEER) Program is NCI’s authoritative source for information about cancer incidence and survival. SEER collects cancer incidence and survival data from cancer registries that cover approximately 26 percent of the U.S. population. Over several decades, SEER has worked diligently to better represent racial, ethnic, and socioeconomic diversity and currently covers 23 percent of African Americans/Blacks, 40 percent of Hispanic/Latinos, 42 percent of American Indians and Alaska Natives, 53 percent of Asian Americans, and 70 percent of Hawaiian/Pacific Islanders living in the United States. In addition, SEER statistics reflect the U.S. population in regard to poverty and education, with both urban and rural groups represented. The Methods for Measuring Cancer Disparities: A Review Using Data Relevant to Healthy People 2010 Cancer-Related Objectives report (http://seer.cancer.gov/publications/disparities/) describes how data are collected to measure cancer health disparities.
The incidence and death statistics presented in this fact sheet are from Tables I-23 through I-28 of the SEER Cancer Statistics Review, 1975-2004 (http://seer.cancer.gov/csr/1975_2004). These statistics are most often reported as the numbers of new cases of invasive cancer and cancer deaths per year per 100,000 persons in the U.S. population. When the statistics focus on cancer incidence and death in a single genderfor example, on female breast cancer or male prostate cancerthe numbers are per 100,000 persons of that gender. In addition, the SEER statistics are age-adjusted to the 2000 U.S. standard population. Age-adjustment is done because different population groups may not be comparable with respect to age. Age-adjustment allows cancer incidence and death statistics (expressed below as cancer incidence and death rates) for these population groups to be compared.
What are the overall cancer incidence and death rates for different populations living in the United States?
Although cancer deaths have declined for both Whites and African Americans/Blacks living in the United States, African Americans/Blacks continue to suffer the greatest burden for each of the most common types of cancer. For all cancers combined, the death rate is 25 percent higher for African Americans/Blacks than for Whites. How do breast cancer incidence and death rates differ for women from different racial or ethnic groups? In the United States, White women have the highest incidence rate for breast cancer, although African American/Black women are most likely to die from the disease. Breast cancer incidence and death rates are lower for women from other racial and ethnic groups than for White and African American/Black women.
What factors might contribute to the higher breast cancer death rate observed in African American/Black women? Lack of medical coverage, barriers to early detection and screening, and unequal access to improvements in cancer treatment may contribute to observed differences in survival between African American/Black and White women. In addition, recent NCI-supported research indicates that aggressive breast tumors are more common in younger African American/Black and Hispanic/Latino women living in low SES areas. This more aggressive form of breast cancer is less responsive to standard cancer treatments and is associated with poorer survival (3).
How do cervical cancer incidence and death rates differ for women from different racial or ethnic groups?
Compared to White women in the general population, African American/Black women are more likely to be diagnosed with cervical cancer. Hispanic/Latino women, however, have the highest cervical cancer incidence rate. Interestingly, White women living in Appalachia suffer a disproportionately higher risk for developing cervical cancer than other White women. The highest death rate from cervical cancer is among African American/Black women.
What factors might contribute to the greater burden of cervical cancer among Hispanic/Latino and African American/Black women?
The disproportionate burden of cervical cancer in Hispanic/Latino and African American/Black women is primarily due to a lack of screening. In an effort to understand this disparity in cervical cancer screening, NCI conducted a study of regions within the United States where cervical cancer incidence rates are high. They found that cervical cancer rates reflected a larger problem of unequal access to health care. The Excess Cervical Cancer Mortality: A Marker for Low Access to Health Care in Poor Communities report (http://www.cancer.gov/about-nci/organization/crchd/about-health-disparit…) supports reaching these medically underserved groups through culturally sensitive trained care providers; increasing the number of female health providers, particularly those of the same race or ethnicity; and removing cultural and economic barriers to break down resistance to screening for cervical and other cancers.
Persistent infection with certain strains of the human papillomavirus (HPV) is the major cause of most cases of cervical cancer. An HPV vaccine is now available that targets two strains of the virus that are associated with development of cervical cancer and account for approximately 70 percent of all cases of cervical cancer worldwide. This vaccine prevents infection by two HPV strains and has the potential to reduce cervical cancer-related health disparities both in the United States and around the world. More information can be found in the NCI fact sheet Human Papillomavirus (HPV) Vaccines.
What factors might contribute to the disproportionate burden of prostate cancer among African American/Black men?
The higher incidence of prostate cancer in African American/Black men compared with men from other racial/ethnic groups prompted the hypothesis that genetic factors might account, in part, for the observed differences. Recent findings from NCI Cancer Genetic Markers of Susceptibility (CGEMS) program (http://cgems.cancer.gov) and other investigations support this hypothesis. Researchers have identified changes called variants in human DNA that are associated with the risk of developing prostate cancer. Different combinations of these variants have been found in men from different racial/ethnic backgrounds, and each combination is associated with higher or lower risk for prostate cancer. Nearly all of the variants associated with an increased risk of developing prostate cancer were found most often in African American/Black men, and certain combinations of these variants were associated with a five-fold increased risk of prostate cancer in men of this racial/ethnic group (4).
In addition, research has shown that low SES, lack of health insurance coverage, unequal access to health care services, and absence of ties to a primary care physician are barriers to screening for prostate cancer and the timely diagnosis of this disease, making African American/Black men less likely to receive regular physical examinations and screening for prostate cancer (5).
Do incidence and death rates differ for colorectal or lung cancer among various racial and ethnic groups?
African American/Black men and women have the highest incidence and death rates for both colorectal and lung cancers, while Hispanic/Latinos have the lowest rates. Which cancers are diagnosed most often in Asian/Pacific Islander populations? Asian Americans and Pacific Islanders have the highest incidence rates for both liver and stomach cancer and are twice as likely to die from these cancers as Whites.
Why is stomach cancer more commonly diagnosed in Asian/Pacific Islander populations?
Asian/Pacific Islanders, similar to Hispanic/Latinos, have lower incidence rates than Whites for most common cancers. However, they suffer more often from cancers that are related to infections. One risk factor for stomach cancer is infection with a bacterium called Helicobacter pylori, or H. pylori. Although additional study is needed, infection with H. pylori may explain, in part, why Asian/Pacific Islander populations have higher rates for this type of cancer.
Which cancer is more commonly diagnosed in American Indian and Alaska Native populations?
American Indians and Alaska Natives have higher incidence and death rates for kidney cancer than other racial/ethnic groups. However, these rates should be viewed with caution because the data currently available for American Indian/Alaska Native populations are not representative. An analysis of cancer incidence and mortality data within Native American populations is the focus of the Annual Report to the Nation on the Status of Cancer 1975-2004, Featuring Cancer in American Indians and Alaska Natives (http://www.interscience.wiley.com/cancer/report2007), a yearly publication that summarizes the latest cancer statistics.
How is NCI working in a coordinated way to reduce cancer health disparities?
NCI has a longstanding history of pursuing research aimed at understanding and addressing cancer health disparities. As many as 20 years ago, NCI established the Special Populations Studies Branch to study groups of people within the United States who suffer a greater burden of cancer. NCI’s commitment to underserved populations continued to grow and mature over the years, and, in 2001, the institute established the Center to Reduce Cancer Health Disparities (CRCHD) to serve as the cornerstone of NCI’s efforts to reduce the unequal burden of cancer in our nation.
Today, CRCHD is working to strengthen and integrate NCI’s studies in basic, clinical, translational, and community-based research that offer opportunities to advance our understanding of cancer-related health disparities and ways to effectively address them. CRCHD manages specific programs and grants aimed at examining the diverse aspects of cancer-related disparities. These programs are addressing the cultural barriers and biases that racial and ethnic minorities encounter in obtaining appropriate and timely treatment, as well as financial and physical restraints that prevent underserved populations from obtaining quality health care. CRCHD is also leading NCI’s efforts to train students and investigators from diverse populations to pursue research in cancer, as well as research examining factors that contribute to cancer health disparities.
CRCHD also cosponsors an annual Cancer Health Disparities Summit. During this 3-day meeting, NCI-funded researchers from training, education, and outreach programs gather to discuss both disparities issues that are present in their communities and possible solutions for these issues.
Selected References
- Surveillance, Epidemiology, and End Results (SEER) Program (http://www.seer.cancer.gov) SEER*Stat Database: Incidence SEER 17 Regs Limited-Use, Nov 2006 Sub (2000-2004) Linked To County Attributes Total U.S., 1969-2004 Counties, National Cancer Institute, DCCPS, Surveillance Research Program, Cancer Statistics Branch, released April 2007, based on the November 2006 submission.
- Surveillance, Epidemiology, and End Results (SEER) Program (http://www.seer.cancer.gov) SEER*Stat Database: Mortality All COD, Total U.S. (1990-2004) Linked To County Attributes Total U.S., 1969-2004 Counties, National Cancer Institute, DCCPS, Surveillance Research Program, Cancer Statistics Branch, released November 2006. Underlying mortality data provided by the National Center for Health Statistics (http://www.cdc.gov/nchs).
- Carey LA, Perou CM, Livasy CA, et al. Race, breast cancer subtypes, and survival in the Carolina Breast Cancer Study.JAMA, 2006; 295(21); 2492-2502.
- Haiman CA, Patterson N, Freedman ML, et al. Multiple regions within 8q24 independently affect risk for prostate cancer.Nature Genetics, 2007; 39(5); 638-644.
- Talcott TA, Spain P, Clark JA, et al. Hidden barriers between knowledge and behavior: The North Carolina Prostate Cancer Screening and Treatment Experience.Cancer, 2007; 109(8); 1899-1606. Reviewed:March 11, 2008
Source:
https://www.cancer.gov/about-nci/organization/crchd/cancer-health-dispar…
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