July 8, 2016 by NCI Staff
The aging of the U.S. population will result in a substantial increase in the number of older cancer survivors over the next quarter century, particularly those 85 and older, according to a new study by NCI researchers.
Using statistical models to analyze population data, the researchers estimated that the overall number of cancer survivors in the United States will continue to grow substantially. But the proportion of survivors who are aged 65 or older will grow the most, with this group representing nearly three-quarters of cancer survivors by 2040, the researchers reported in a study published July 1 in Cancer Epidemiology, Biomarkers & Prevention.
“Current U.S. demographics will literally change the face of the survivor population in the decades to come,” wrote Shirley Bluethmann, Ph.D., M.P.H., of NCI’s Division of Cancer Control and Population Sciences (DCCPS), who led the study with her DCCPS colleagues.
A “Silver Tsunami” of Cancer Survivors
The number of long-term cancer survivors has continued to grow over the past several decades. With this growth has come the recognition that many cancer survivors have unique health care needs as a consequence of their cancer or the treatments they received.
Concerns have been raised about whether the health care system has the capacity to satisfy the growing demand for cancer and survivorship care, with physician organizations forecasting shortages of oncologists and family physicians, both of which represent the primary medical providers for cancer survivors.
And the strain on the system is only expected to worsen as the U.S. population ages. Every day, thousands of “baby boomers” are turning 65 years old, and many of those with cancer will also have other medical conditions, from cardiac and respiratory diseases to diabetes and rheumatologic conditions.
These trends, the NCI researchers wrote, “foreshadow a ‘silver tsunami’ of cancer survivors whose health needs we are unprepared to meet.”
To better understand the composition of the cancer survivor population and their other medical conditions, or comorbidities, the researchers made projections based on data from NCI’s Surveillance, Epidemiology, and End Results (SEER) program, including the SEER-Medicare linked database, and the U.S. Census Bureau.
By 2040, the researchers estimated, the number of cancer survivors in the United States will increase by nearly 11 million: from 15.5 million in 2016 to 26.1 million in 2040. Moreover, they found, the makeup of the cancer survivor population will change substantially over that time period, with the proportion of survivors aged 65 or older increasing from 61% to 73%. By 2040, only 18% of cancer survivors will be between ages 50 and 64, and only 8% will be younger than 50.
A unique aspect of this study, Dr. Bluethmann explained in an interview, was that the researchers were able to assess specific cancer burden by age groups of older survivors.
“Many studies tend to group all older people together into a category of ‘ages 65 and older,’” she said. “But, we know that the health and function of older adults is extremely diverse and thought it would be valuable to provide more discrete estimates of prevalence across the older population of survivors.”
For example, they estimated that by 2040, a sizable portion of the older survivor population will be aged 85 or older. In fact, when they extended the starting point for their analysis back to 1975, they estimated that those aged 85 and older would have the sharpest increase in the number of cancer survivors by 2040.
The researchers also used SEER and Medicare data to assess the current extent of comorbidities in cancer survivors aged 65 and older compared with people in the same age range without a history of cancer. They tracked the prevalence of 16 common conditions that had been assessed in earlier population-based studies of older people, including a history of heart attack, liver disease, diabetes, and vascular conditions.
Overall, the comorbidity burden tracked more closely with age than with whether somebody had a prior cancer diagnosis. For example, the comorbidity burden among cancer survivors aged 66–74 was similar to the burden in the noncancer population of that age group.
But, not surprisingly, the extent of severe health problems in both cancer survivors and people without a history of cancer increased dramatically with age. For instance, 26% of survivors and 16% of those without a cancer history in their late 60s had severe comorbidities, compared with 47% and 42%, respectively, of those aged 85 years and older.
Cancer site also appears to be an important factor in comorbidity burden, the researchers found. In particular, most lung cancer survivors had a severe comorbidity burden compared with survivors of other cancer sites, even in the 65-69 age group.
The authors cautioned that their study may underestimate the extent of comorbidities among cancer survivors because it did not include other conditions—such as high blood pressure, arthritis, and atrial fibrillation—that are common in older populations and because medical records often don’t capture all of a patient’s health conditions.
Changes Needed to Address Older Survivors’ Needs
The findings from this study and others make it clear that important changes are needed to meet the needs of older cancer survivors, noted study coauthor Julia Rowland, Ph.D., director of NCI’s Office of Cancer Survivorship.
Those changes include enrolling more older and elderly patients in clinical trials, which will help researchers and clinicians better understand age-appropriate treatment plans and potentially reduce long-term treatment-related side effects. Greater participation by older adults in clinical trials may also provide much needed information about support resources and programs for cancer survivors in long-term recovery, Dr. Rowland said.
“Most older adults diagnosed with cancer present with two or more comorbid conditions,” she continued. “Figuring out how to manage these in the context of cancer is an important goal.”
And the expanding population of survivors clearly has repercussions for how their medical needs will be met, Dr. Rowland continued.
“Training diverse providers—including nurses, nurse practitioners, and physician assistants—to help with cancer-specific follow-up may be important to assist in the growing burden of caring for older survivors,” she said.
Many informal caregivers of cancer survivors are poorly equipped to meet the demands of providing routine medical care to their loved ones. So Dr. Rowland said that researchers also need to continue to assess the impact of caregiving on these informal providers, including whether providing them with training “can improve their health as well as that of their loved one.”