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Cancer care disparity is a complex issue, as it is both a medical and a socioeconomic issue. A discussion of the issues inherent to cancer care disparities should first define cancer care disparity and identify which populations are classified as disparate. As each population is identified as disparate, one can then discuss the causes of outcome differences in disparate versus nondisparate populations. In doing so, a discussion can then reflect on how differences in primary and secondary preventive practices, and ultimately, tertiary interventions affect the health outcomes of persons identified within these populations.
Socioeconomic factors are the most universal contributors to cancer outcome disparity. They include the patient’s or guardian’s education level, whether the patient has health insurance or a contract with a third-party payer, and access to effective health care. Living conditions or exposures to environmental toxins, lifestyle choices such as diet and exercise, excessive alcohol and tobacco use also affect cancer care outcomes.1-3
Research on cancer care disparity outcomes has focused on the major malignancies (colorectal, lung, and breast cancers, and occasionally cervical and prostate cancers) because large populations can be studied.3-5 The factors used in these studies are socioeconomic status, minority status, adherence to primary and secondary preventive measures, and tertiary interventions. This article reviews the impact of disparities on outcomes at each level of cancer care.
DEFINING THE TERMS
The National Cancer Institute (NCI), after multiple projects and studies on the issue, established a standard definition. The NCI defines cancer care disparities as “adverse differences in cancer incidence (new cases), cancer prevalence (all existing cases), cancer death (mortality), cancer survivorship, and the burden of cancer or related health conditions that exist among specific population groups in the United States.”6,7
Primary intervention refers to reducing the incidence of cancer through lifestyle and behavioral changes. Secondary interventions are the various screening techniques used to detect cancer early enough to positively affect the outcome. Tertiary interventions are the team modalities used at various stages once the cancer has been diagnosed.8,9
Factors used to identify a disparate population may include age, race, disabilities, socioeconomic status, education level, and gender. In regard to heath-related issues, however, socioeconomic status tends to have the greatest influence on disparities. A greater incidence of some behavioral factors (eg, smoking or obesity) among socioeconomic disparate populations is reported, in addition to limited access to health care.1,3,6
PRIMARY PREVENTIVE MEASURES
Primary interventions, activities such as exercise, obesity reduction, avoiding environmental situations conducive to malignancies, and avoiding smoking and excessive alcohol use, can decrease the risk of cancer. Disparate populations have traditionally had a reduced participation in healthy lifestyle practices. Disparate populations tend to have a higher level of obesity, greater incidence of smoking, and excessive use of alcohol, which likely leads to a higher incidence of cancer in these groups.1,10-13 Genetic or heredity risk factors cannot be controlled and also play a role in cancer incidence.
These unhealthy lifestyle choices not only increase the incidence of cancer, they also increase the mortality rates from other major illnesses such as diabetes and heart disease. Even within the cancer diagnoses, evidence shows that some forms of cancer have a worse prognosis when associated with a particular habit.14 For example, adenocarcinoma of the lung is statistically more likely to respond to certain biologic therapies, and therefore result in improved survival, if the patient is a nonsmoker.14,15
Obesity is often overlooked in relation to a cancer diagnosis. Medical science is just beginning to understand the relationship between up regulation of insulin requirements and carcinogenesis.10,16 While many may believe that excess adipose tissue is an advantage once cancer is diagnosed, this theory ignores its possible contributory role in the development of malignancy.
Certain vaccinations have gone a long way toward preventing cancer. In the United States, mandatory administration of the hepatitis B vaccine at birth has rendered hepatocellular carcinoma, a common malignancy through the world, a rare disease in the United States. Conversely, underuse of human papillomavirus (HPV) vaccination in disparate populations has led to increased concerns about clustering of head and neck, cervical, and anal cancer among these groups.17-19 There is often a lack of understanding that even with such preventive programs as HPV vaccination, participants should understand the importance of continued surveillance, as the vaccine is not meant to replace Pap tests and pelvic examinations.
Lifestyle choices have a major impact on cancer risks throughout the world. Among disparate populations in developing or third-world countries, primary cancer prevention must focus additionally on minimizing cancer-associated infections such as hepatitis B and adequate nutrition to maintain a healthy immune system.
SECONDARY PREVENTIVE MEASURES
Screening techniques or secondary interventions for certain types of cancer are underutilized in disparate populations.20-23 Availability of screening techniques is often limited because the primary disparity is economic. For example, among many disparate urban populations and rural communities, patients undergo colonoscopy after symptoms of colorectal cancer develop more often than for screening purposes; likewise, mammography is used more frequently for women with palpable breast abnormalities as opposed to screening asymptomatic women.24,25 Although Pap tests and pelvic examinations for cervical cancer were the first and foremost form of secondary prevention, a high degree of nonparticipation in cervical cancer screening still exists among disparate populations, especially the uninsured and under-insured.18,26
IMPACT OF SCREENING CONTROVERSIES
Some areas of cancer screening have become quite controversial. The reliability of using prostate-specific antigen (PSA) levels and CA-125 biomarkers to detect prostate cancer and ovarian cancer, respectively, is frequently debated. Because the value of these screening techniques has yet to be established, a lack of access to these tests has not resulted in a significant disparity in cancer outcomes.9,27,28 In some populations, particularly African American females, undergoing mammography may not have a significant impact on outcome. A higher incidence of triple-negative breast cancers is seen in these populations, and the prognosis for this cancer is significantly worse than other breast cancers, even with early detection.29,30