Aging in the context of cancer prevention and control

Abstract

Men and women aged ≥65 years represent approximately 12% (36.8 million) of the US population and this number is expected to double by the year 2030.1 The fastest growing segment of the population is the “oldest old,” those aged ≥85 years. Projections suggest that the oldest old will have increased in number from 3.7 million in 1996 to 5.7 million in 2010 and could reach 18.2 million by 2050.1 Research clearly demonstrates that the risk of cancer increases with age.2,3 Approximately 60% of all incident malignancies in the US occur in adults aged ≥65 years and 16% of those aged ≥65 years have a history of cancer.2 Although cancer is the second leading cause of death among men and women aged ≥65 years,1 many older adults are in fact surviving cancer. In the US alone, it is estimated that 6.5 million of the 10.8 million cancer survivors are aged ≥65 years, with the oldest old comprising 15% of this 6.5 million (Fig. 1). Approximately 43% of these elderly men and women with cancer survive >10 years and approximately 17% survive >20 years from the time of their initial diagnosis.2 FIGURE 1 Estimated number of cancer survivors aged >65 years in the US on January 1, 2004 by age group (invasive/first primary tumor cases only [N = 6.5 million survivors aged >65 years]). Data source: Surveillance, Epidemiology, and End Results ... For many older adults, cancer appears to be joining the ranks of other age-related chronic diseases, but the post-treatment burden of the disease (eg, loss of physical function, permanent disability, fatigue, insomnia, depression, anxiety, and economic devastation) is relatively unknown in this growing population. We know from studies of pediatric and younger adult cancer survivors that cancer and its treatment can result in years of physical and mental distress for some individuals.4,5 These chronic consequences can significantly impair the health and quality of life of cancer survivors and their caregivers beyond what is typical of adults without cancer. The chronic physical and mental distress associated with cancer survivorship exacerbates and is exacerbated by the additional comorbid conditions (eg, hypertension, hypercholesterolemia, osteoporosis, diabetes, and dementia) often present in adults aged ≥65 years6–9 and health disparities are typically present in underserved populations because of age, sex, race, sexual orientation, and nationality. It is imperative that healthcare practitioners and researchers from disparate disciplines collectively focus efforts toward gaining a better understanding of what the consequences of cancer and its treatments are for older adults and how to appropriately meet the multifaceted medical and psychosocial needs of this growing population. Preventing and attenuating the chronic consequences of cancer and its treatments among older adults is critical to improve not only the individual’s quality of life but also to reduce the additional public health burden on the US healthcare system. At the same time, cancer care for older adults should extend throughout the illness and incorporate appropriate palliative management at the end of life for those who will die at an advanced age, particularly the oldest old. The cancer and aging trends described above illustrate a major public health challenge that healthcare professionals will soon face in caring for this growing population. Unfortunately, to our knowledge, evidence–based practice guidelines regarding the short–term and long–term management of cancer, including palliative care, is sparse for this group and it would be inappropriate to extrapolate from extant studies on younger populations because older adults are physiologically, psychologically, and socially different from younger adults.10–12 The aging process involves several normative physiologic changes, such as increases in blood pressure, arteriosclerosis, the reduced effectiveness of cytotoxic T lymphocytes and natural killer cells, functional changes in the gastrointestinal system and lungs, and an overall decrease in reserve capacity.10,13 The extent to which age-related physiologic changes affect disease progression, response to treatment, survivorship, and the management of palliative care issues in older adults is unknown. Unlike younger adults, the experience of cancer in the elderly is often superimposed on existing health conditions, including heart disease, arthritis, diabetes, and various geriatric syndromes that affect older adults.7,14,15 These coexisting medical conditions, often the focus of cancer and aging research, can complicate prevention and screening efforts and the efficacy of and extent of the treatment offered, as well as older adults’ response to treatment and post-treatment health and well-being. From a psychologic standpoint, the gerontology literature reveals that many older adults perceive less control over their health, experience fewer emotional highs and lows, and adjust their expectations and attitudes regarding their current state of health and/or ability to recover from adverse health events as they age.11,16–18 In addition, many older adults have had previous experiences with health issues, multiple cancer diagnoses, and other life losses due to their placement in the life course.19 The extent to which life experiences influence current beliefs and attitudes regarding prevention and screening practices or resiliency during the survivorship experience warrants consideration as the nascent field of cancer and aging evolves. Socially, growing older brings about some important changes in work life, relationships with family and friends, and roles and responsibilities.12,17 Given that older adults have many more options today to be active members of their community, the timing of changes and the extent to which modifications in roles and responsibilities affect the older adult’s health can vary greatly. Research suggests that older adults, who do not replace previous social roles, can end up socially isolated, which can ultimately lead to poorer health outcomes.20 Understanding aspects of social development (ie, role continuity, role loss, and role gain) are important considerations, often overlooked in oncology, for future research on older individuals with cancer. These developmental domains also need to be considered when providing palliative care to patients who will die of their cancer or competing health conditions. Assessing a person’s psychologic, social, and existential response to illness, as well as medical aspects of the disease, is an important feature of whole–patient palliative care and disease management.21,22 Understanding patient and family preferences and desires for care, including hospice care, extent of palliative care, and advanced directives, are also critical elements of comprehensive cancer care. As we age, we become more heterogeneous in terms of physical and psychosocial health as a result of our previous lifestyle, environmental exposure, and genetic composition.13 As a result, age should not be used as a proxy for health status23 and categorizing men and women aged ≥65 years as 1 homogeneous group does a disservice to the population that we are trying to serve. In the US, an elderly person is arbitrarily defined as someone aged ≥65 years for bureaucratic reasons, yet many healthcare professionals make critical medical care decisions based on this artificial cutoff.24 New strategies are needed to assess the health status of older adults, which could include the use of comprehensive geriatric assessments and performance–based measures, as well as emerging biomarkers of physiologic age.25–27 Understanding within–group variations among older adults across the cancer control continuum requires that more attention be paid to aspects of physiologic, psychologic, and social development and less to chronologic age. Regrettably, research has not kept pace with this rapidly growing segment of our population. Therefore, we are left devoid of information regarding the salient and often complex health issues and needs of this group. Recognizing this gap in knowledge, the Institute of Medicine convened a meeting to elucidate some of the key issues affecting the elderly and how age–related issues can complicate the treatment and acute medical management of cancer.28 In 2007, an entire issue of the Journal of Clinical Oncology was dedicated to the evaluation and treatment of elderly cancer patients.29 Although these 2 publications illustrate some of the important challenges we face in caring for this population, the focus of these 2 efforts were primarily from a medical perspective highlighting cancer and aging issues related to treatment of the disease. To our knowledge, the extent to which the development and integration of psychosocial, behavioral, and biomedical knowledge might help inform the emerging field of cancer and aging has yet to be explored.