Stuart M. Lichtman, MD
Geriatrics for the Oncologist is guest edited by Stuart M. Lichtman, MD, and developed in collaboration with the International Society of Geriatric Oncology (SIOG). Dr. Lichtman is an Attending Physician at Memorial Sloan Kettering Cancer Center, Commack, New York, and Professor of Medicine at Weill Cornell Medical College, New York. He is also President Elect of SIOG. For more information about geriatric oncology, visit www.siog.org and the new ASCO Geriatric Oncology website (www.asco.org/practice-guidelines/cancer-care-initiatives/geriatric-oncology/geriatric-oncology-resources).
The prevalence of both cancer and cognitive impairment increases with age.1-3 Based upon Surveillance, Epidemiology, and End Results (SEER)-Medicare studies, it is estimated that 3% to 7% of patients with cancer aged ≥ 65 also suffer from dementia, although the true prevalence of dementia in this population is likely higher, given the probable lack of capture in claims data.4,5 This figure also does not include individuals with mild cognitive impairment, an earlier stage of memory loss. Mild cognitive impairment affects an estimated 22.2% of Americans over the age of 70.2
Impact of Chemotherapy on Cognition
Previous studies have demonstrated the negative impact of cancer and cancer therapy on cognition. Chemotherapy-related cognitive impairment has been reported in several studies, although the majority were conducted in younger patients with cancer.6 A few smaller studies have prospectively evaluated cognitive function in older adults or have included older adults in subset analyses.
Hurria and colleagues evaluated the cognitive status of 28 women aged ≥ 65 with breast cancer receiving adjuvant chemotherapy.7 Patients underwent neuropsychological and geriatric assessments prior to receiving adjuvant chemotherapy and again 6 months after completion of treatment. At 6-month follow-up, over one-third of patients demonstrated decline in cognitive function, although no significant changes in functional measures, including activities of daily living, instrumental activities of daily living, or performance status, were noted.7
Both cancer and cognitive impairment are associated with aging. Given the complexities of cancer therapy, many older adults need enhanced support to navigate treatment.— Allison M. Magnuson, DO
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Ahles and colleagues performed a similar study of cognitive function in patients receiving adjuvant chemotherapy for breast cancer and included a subset of older patients (age > 60). They observed that older patients with low cognitive reserve at baseline (assessed by reading ability) had the lowest performance on processing speed at follow-up, suggesting that older adults with preexisting limitations in cognition may be the most vulnerable to cognitive changes after exposure to chemotherapy.8
No prospective studies have been conducted in older adults with preexisting mild cognitive impairment or dementia who receive chemotherapy. Observational studies are needed to understand the impact of chemotherapy on cognition, functional status, and independence level in this vulnerable group.
In oncology, cognitive assessment is not routinely performed in older adults. Given the complex decisions regarding treatment options and complicated cancer regimens that patients often face, however, it seems advisable to perform a cognitive assessment to determine whether an older adult is able to engage in the decision-making process and manage the complexities of cancer therapy. Studies are needed to identify feasible methods to incorporate cognitive screening into routine oncology practice, so providers can identify and support this vulnerable population.
Several cognitive assessment screening tools exist, including the Montreal Cognitive Assessment, the Mini-Mental State Exam, the Blessed Orientation-Memory-Concentration test, and the Mini-Cog.9-12 The Mini-Cog is the shortest of these tools and takes approximately 3 minutes to administer.12 The Mini-Cog has been compared with the Mini-Mental State Exam in older adults with cancer and was found to have good sensitivity and specificity, at 80.7% and 83.8%, respectively, for identifying cognitive impairment.13
To date, no studies have evaluated the risks of chemotherapy and treatment-related adverse events in older adults with preexisting cognitive impairment. Two models to predict chemotherapy toxicity in the general older adult population have been developed: the Chemotherapy Risk Assessment Scale for High-Age Patients and the Cancer and Aging Research Group tool.14,15 The Chemotherapy Risk Assessment Scale for High-Age Patients identified baseline changes in cognition (defined as Mini-Mental State Exam < 30) as a risk factor for nonhematologic toxicity; however, the Cancer and Aging Research Group tool did not identify baseline cognitive changes as a risk factor for chemotherapy toxicity, although a different cognitive assessment (Blessed Orientation-Memory-Concentration test) was used in this study.
When preexisting cognitive impairment is identified, several supportive care strategies can be implemented along with cancer therapy.16 A Delphi study of geriatric oncology experts summarized recommendations for supportive care interventions for adults with cognitive impairment.17 Recommendations from this expert panel included caregiver involvement, minimizing complexity of treatment and medications, delirium prevention, social work involvement, capacity assessment, health-care proxy identification, and additional cognitive testing/neuropsychological assessment. Although interventions have not been specifically evaluated in older adults with cognitive impairment receiving cancer therapy, these strategies were extrapolated from evidence and practices in the general geriatrics population with cognitive impairment.
Given the complexities of cancer therapy, many older adults need enhanced support to navigate treatment. Older adults may live alone in the community, and enhanced social support can help with monitoring for and managing side effects, managing complex medication regimens, and transportation for office visits and treatments. Options for enhanced social support include recruitment of family or friends, home health aides or nursing support, meals on wheels, transportation assistance, and social work involvement. Occasionally patients with more significant baseline cognitive impairment may require 24-hour supervision to enhance safety and monitor side effects.
If older adults with cognitive impairment experience declines in cognition, they may develop difficulties managing their instrumental activities of daily living, such as managing finances or driving, which may compromise their ability to continue to live independently. Counseling patients and families about the potential impact of cancer therapy on cognition and independence level is important, so proactive measures can be taken to enhance support.
Both cancer and cognitive impairment are associated with aging. The interplay between cognitive impairment and cancer in older adults is becoming increasingly relevant with the aging of our population. Screening for cognitive impairment in the oncology setting is encouraged, and several brief screening tools exist. For individuals with cognitive impairment, supportive care recommendations as previously outlined can be considered. ■
Disclosure: Dr. Magnuson reported no potential conflicts of interest.
1. West LA, Cole S, Goodkind D, et al: 65+ in the United States: 2010. U.S Department of Commerce, Economics and Statistics Administration, U.S. Census Bureau. 2014. Available at https://www.census.gov/content/dam/Census/library/publications/2014/demo/p23-212.pdf. Accessed December 6, 2016.
7. Hurria A, Rosen C, Hudis C, et al: Cognitive function of older patients receiving adjuvant chemotherapy for breast cancer: A pilot prospective longitudinal study. J Am Geriatr Soc 54:925-931, 2006.
8. Ahles TA, Saykin AJ, McDonald BC, et al: Longitudinal assessment of cognitive changes associated with adjuvant treatment for breast cancer: Impact of age and cognitive reserve. J Clin Oncol 28:4434-4440, 2010.
13. Ketelaars L, Pottel L, Lycke M, et al: Use of the Freund clock drawing test within the Mini-Cog as a screening tool for cognitive impairment in elderly patients with or without cancer. J Geriatr Oncol 4:174-182, 2013.
14. Extermann M, Boler I, Reich RR, et al: Predicting the risk of chemotherapy toxicity in older patients: The Chemotherapy Risk Assessment Scale for High-Age Patients (CRASH) score. Cancer 118:3377-3386, 2012.