Health-related outcomes in cancer survivors

PL05-02

In the United States, health disparities exist in the field of medical oncology. Five-year survival after a cancer diagnosis is poorer for African-Americans than for Caucasians - from 1992 to 1997, the figures were 52% and 63%, respectively. Understanding the role of race and ethnicity is therefore important in reducing health disparities, particularly as they relate to cancer. However, race and ethnicity are composite terms that encompass socioeconomic status, as well as sociocultural and environmental factors. Factors such as health behaviors, health care access, and cancer knowledge are related to income and education, and therefore, the “race effect” may very well be a socioeconomic effect. Large, well-designed epidemiologic studies have explored possible reasons for the survival disparity by examining differences in factors such as stage at diagnosis, socioeconomic status, and health insurance coverage. Although ethnic and racial differences in these factors are present, they do not appear to be entirely responsible to explain the observed differences in survival. The theory that cancers may be fundamentally more aggressive due to biological or genetic differences has therefore gained prominence, but has not been fully explored. Another factor that may reduce longevity includes lesser quality treatment - an observation supported by the fact that African-American patients are less likely to receive chemotherapy, radiation therapy or surgery, and by the fact that similar survivals have been documented for patients who received similar treatments. There is some evidence that African-American patients experience higher rates of complications; take longer to complete chemotherapy than Caucasians and are less likely to complete chemotherapy than Caucasians. Studies have also demonstrated that African-American patients are less likely than Caucasians to receive surveillance, thus explaining the more advanced stage at diagnosis observed in the former. Differences in survival could also be explained by greater mortality due to pre-existing comorbidities. Rates of death because of cardiovascular disease, diabetes, and other major illnesses are greater for African-Americans than Caucasians. The overall impact of comorbidities such as obesity and physical activity in explaining differences in the cancer survival has not been examined completely.
 Access to care, trust of the medical system, and discrimination in the system are likely important variables, but differences in lifestyle, comorbidities, and tumor biology and genetics should not be ignored. Continued understanding of why there are differences in the receipt and the benefit of treatment are equally important factors. Acknowledging that this is a multifaceted problem with no single solution necessitates addressing the issue by breaking it into smaller components. Such a strategy is currently being executed in an NCI-funded study attempting to understand ethnic/ racial differences in survival in children treated on cooperative group therapeutic trials for childhood acute lymphoblastic leukemia (ALL). African Americans and Hispanics have significantly lower disease-free survival, when compared with Caucasians. These differences persist after adjusting for known factors that predict disease-free survival. Several reasons unique to childhood ALL and its management could contribute to these differences, and are currently being explored. Thus, the study is geared to examine differences in disease biology, extent of disease, treatment protocol, pharmacogenetics, drug bioavailability, adherence to therapy, socioeconomic status, demographic characteristics, and, using the health-belief model, the level of understanding of the disease by the patient and their caregivers. Results of this study should form a basis for targeted interventions that would help ameliorate the differences in outcomes by race and ethnicity.
 Until recently, cancer care focused almost exclusively on the aggressive pursuit of a cure and, when that was not possible or efforts failed, on helping patients die with minimal suffering. In the world today, there are roughly 25 million cancer survivors, of which more than 10 million are in the United States alone. The number of cancer survivors is expected to grow as new advances in cancer screening and treatment diffuse into the community, and with the aging of the population. Today we are in an enviable position of being able to champion an approach to cancer care that includes care for cancer survivors living well beyond the time their cancer is diagnosed and treated. As researchers continue to search for cancer cures, health care providers in collaboration with a variety of partners have an obligation to help cancer survivors and their family members address issues related to long-term survival. While these issues have been researched over the last two decades in the world of pediatric oncology, the adult oncology patients are becoming the subject of such scrutiny as a result of a series of reports published by the Institute of Medicine.
 Even less is known about disparities in long-term physical and medical aspects of cancer survivorship. Cancer survivors are at an increased risk of second cancers, other forms of comorbidity (cardiovascular disease, diabetes, osteoporosis), and functional decline. Gaps exist in our understanding of the burden of chronic and late effects of many of the standard and most of the newer cancer treatments by race and ethnicity. Compared with Caucasians, African-Americans and Hispanics are considered vulnerable populations for adverse health outcomes in both the general US population, and medical oncology. Socioeconomic differences and a higher prevalence of comorbid conditions in African-American adults are associated with poorer outcomes in medical oncology settings. Hispanics are reported to underutilize the cancer screening recommendations and services and are most likely to be uninsured. However, we do not know whether the chronic and late effects of cancer treatment differ by race and ethnicity, and whether the differences can be ameliorated. Appreciating these adverse sequelae and finding means to prevent or ameliorate them in a culturally competent manner are important challenges for clinicians and researchers. Questions related to how best to deliver optimal follow-up care - who should deliver it, in what settings, for how long, at what cost and according to which guidelines or best practice models - represent our present day challenges. Cancer survivors also face a host of challenges to their long-term psychological functioning, as well as economic well-being. While most women experience good health-related quality of life (HRQL) after completion of treatment for breast cancer, African-American women report lower physical functioning scores and Hispanics report more physical symptoms, compared with Caucasian and Hispanic women. However, African-Americans report higher mental health scores, and find more meaning in life as a result of having breast cancer. Lifestyle factors, such as healthy diet, regular exercise, and smoking cessation could help prevent these conditions and improve survivors’ quality of life - but the role of psychosocial or behavioral interventions in reducing morbidity has not been rigorously examined. Finally, barriers faced by cancer survivors in receiving primary and secondary prevention interventions as recommended by the US Preventive Services Task Force have not been explored.
 Large comprehensive studies examining the multiple facets of cancer survivorship in a multiethnic cohort are critically needed to understand the needs of cancer survivors and set the stage for providing such care and developing interventional strategies to reduce morbidity and mortality. Utilizing the resources offered by the Childhood Cancer Survivor Study, investigators compared differences in health outcomes, healthcare utilization, health practices and health behaviors between adult African-American, Hispanic and Caucasian survivors of childhood cancer. Hispanics and African-Americans were more likely to have lower socioeconomic status. After adjusting for income, education, and health insurance, the overall health status was similar; however, African-Americans were less likely to report adverse mental health. Differences in healthcare utilization and behavior models were noted: Hispanic survivors were more likely to report a cancer center visit; African-Americans were more likely and Hispanics less likely to have a recent Pap smear; African-American and Hispanic survivors were less likely to report smoking; and African-American survivors were less likely to report problem drinking. African-American female survivors were more likely to report compliance with sex-specific screening in comparison with Caucasian survivors - mirroring rates reported by African-American women nationally after decades of targeted community programs in this population. On the other hand, the lower Pap smear screening rates in Hispanic survivors mirror findings in the general Hispanic population.
 One in three cancer survivors will develop a severe or life-threatening illness. There is a critical need to understand the unique ways in which race and ethnicity impact on health-related outcomes in cancer survivors. Recognizing that race and ethnicity are composite terms that encompass socioeconomic status, cultural, and environmental factors, there is a need for large, systematic studies focusing on all aspects of cancer survivorship, with the overall goal of identifying vulnerable populations. These would then inform the culturally targeted interventions to reduce the burden of morbidity carried by the cancer survivors.