Overall prevalence rates among cancer survivors continue to rise. Forty years after the passage of the National Cancer Act, we have witnessed a four-fold increase in the number of U.S. cancer survivors from 3 million to close to 12 million. Advances in the treatment and early detection of cancer, in concert with increased life expectancy and a growing aged population are contributing to the rising number of cancer survivors in the United States. The projections reported here represent the most recent data on cancer prevalence and aging and provide projections of the number of older adult cancer survivors through the year 2020. The findings suggest the coming decades will witness a significant increase in the number of those aged 65 and older living long-term with a cancer history. By the year 2020, an estimated 11 million survivors will be older adults, representing a 42% increase in their numbers in just one decade (2010–2020). Moreover, as shown in , the majority of these individuals will be in the survivorship phase following treatment, disease-free or managing chronic conditions, both of which require surveillance and delivery of follow-up care. These trends have important implications for research and planning for future healthcare needs.
Older adults are an overlooked, understudied, underserved, and vulnerable group of cancer survivors. In an internal 2009 portfolio analysis of NIH funded grants addressing survivorship outcomes, fewer than 10% of identified studies focused exclusively on the health and well-being of individuals aged 65 and older. While the number of grants focused on the health and well-being of older adult survivors has been rising slowly, it remains low relative to the number of studies conducted among younger survivor populations. Prospective epidemiological studies of older adult survivor populations are urgently needed. We need to know if older adults’ post-treatment health profiles and patterns of persistent and long-term cancer-related effects differ markedly from those of younger survivors or older adults’ peers unaffected by cancer. How do the presence and progression of pre-existing comorbid conditions and age-related health declines interact with the chronic and late effects of cancer? Do interventions addressing the chronic and late effects of cancer developed with younger survivors work for older adult survivors? Prospective data collection and systematic surveillance of cancer care delivery patterns in older adult cancer survivors are also needed. Is the follow-up care received by older survivors different than that for younger survivors and what are the ramifications of this on patterns of morbidity and mortality? These data should include population-based studies, case-control studies, and intervention trials, and should represent research conducted at both NCI-designated comprehensive cancer care settings and community-based settings (27
). Within studies of cancer survivors, population-based data (such as that collected by cancer registries) should consider inclusion of comorbidity as a standard data element (20
). More cancer clinical trials are needed that include adults age 65 and older, many of whom may have pre-existing health conditions and functional limitations, and are often excluded from cancer-related research studies and therapeutic trials specifically (28
). These will require trial designs that include and thoughtfully consider the effects of concurrent health conditions, rather than exclude them (29
). Clinical trials specifically tailored to older adults are also needed to identify which older adults are at greatest risk for declines in health and psychosocial well-being, to assess treatment tolerance, and to develop and test rehabilitation interventions to help older adults regain functionality after cancer treatment (27
From a conceptual standpoint, future research on older adults cancer survivors should seek to 1) include psychosocial, behavioral, physiological, and health services outcomes; 2) span the survivorship continuum (from primary to quaternary prevention) (31
); 3) differentiate age, period and cohort effects (23
); and 4) explicitly attend to the heterogeneity and diversity of the older adult cancer survivor population. Older adults are a diverse population across physical, social, psychological, economic and cultural dimensions (32
). Further, the expectations of the Baby Boomer generation of older adults for “adequate functional status” may be drastically different from the expectations of previous generations. Given this heterogeneity, assessment of functional status, cognitive status, lifestyle behaviors, health-related quality of life, and social support is likely to provide more useful markers for cancer-related outcomes, surveillance and follow-up care needs than chronological age alone. Beyond inclusion of the areas and topics suggested above, it is critical that psychosocial, behavioral and biomedical knowledge be integrated in future research and translated expeditiously into practice (34
The data reported in this paper have important implications for health services delivery. As reported by Mariotto et al. (11
), the current costs associated with cancer care are estimated at 157.77 billion 2010 U.S. dollars, with the potential to reach173 billion U.S. dollars by the year 2020. The aging of our population contributes significantly to these estimates. The interaction of chronic and late effects of cancer with extant or developing comorbid conditions may lead to more complex medical and psychosocial care needs among older cancer survivors. Because older cancer survivors are likely to be receiving care from multiple providers, they may be exposed to additional risks associated with fragmented care provision (36
) and polypharmacy (37
). Current approaches to improving the quality of care during and after treatment involve the use of treatment summaries and care plans, shared care models for post-treatment healthcare delivery, cancer navigator models, and electronic health records to promote information exchange (39
). To effectively meet the needs of older adults, models for best practice in cancer care will need to address not only the communication and coordination of care on the provider side of the equation, but also on the consumer side. Efforts will be necessary to empower and facilitate older adults’ ability to get their needs met in a fragmented system where mastery of a daunting new array of modern electronic tools (electronic health records, personal data chips, internet use, PDA technology) may be critical to successfully navigating the multiple disciplines and specialties of medicine typically accessed by older adults. Provision of high quality care for older adult survivors may require adoption of new metrics and strategies. These include the use of geriatric assessments of health and quality of life, the development of geriatric cancer rehabilitation programs, and the development of multidisciplinary teams with expertise in older adults’ complex and unique needs. Optimally, these teams will include geriatric specialists in social work, psychology (or neuropsychology), nursing, rehabilitation, and oncology, along with geriatricians. Health services delivery systems face stark challenges as the increasing prevalence of older cancer survivors is accompanied by impending workforce shortages in social work, oncology and geriatrics (41
). Shared care and multidisciplinary models offer a means of more efficiently utilizing the skills of these providers.
Strengths and Limitations
Among the strengths of this inquiry are its generation of U.S. population-based cancer prevalence rates using an innovative algorithm to impute and estimate U.S. prevalence counts and proportions from the most established and highest quality SEER-9 registries, representing approximately 10% of the U.S. population. The findings in this report are subject to a few limitations. First, we projected race- and age-specific proportions from SEER to the U.S. population. Compared to the U.S. population, the SEER population is more urban and has more people who are foreign-born and/or of lower socioeconomic status (1
), which limits the generalizability of these findings. Second, persons with multiple primary tumors were categorized according to their first tumor; so the number of survivors by specific cancer sites may be underestimated (24
). Third, prevalence is projected under the assumptions of current levels of incidence and survival and dynamic projections of age and size of the U.S. population. These projections can be interpreted as the effect of the growth and aging of the U.S. population, under current cancer control technologies. There is no question that if screening and treatment improve, the number of survivors living long-term will increase. However, the aging of the U.S. population makes the greatest contribution to increasing cancer prevalence. Fourth, we were unable to specify whether a survivor was cured, in active therapy, living with a chronic illness or disability, or dying from cancer. Finally, what these prevalence figures do not tell us is the health status of those who are survivors at any given point in time. This is an enduring and troublesome limitation of the current SEER resource platform.
The observed trend of increasing cancer prevalence rates is expected to continue. This trend is compounded by the anticipated growth in the proportion of cancer survivors who are age 65 and older, many of whom may be expected to have concomitant and complex issues associated with aging. If we are to successfully reduce the burden of cancer in the United States, a concerted effort is needed to better describe this growing population, to define and refine standards of quality care for older adults with cancer, and to develop delivery systems that reflect the multifaceted needs of this diverse and vulnerable population.