The population of the United States and other industrialized nations is aging rapidly. The increased life span allows for longer exposure to carcinogens and the accumulation of genetic alterations. Thus, the incidence of cancer is increasing along with the aging of the population. Patients aged ≥ 65 years account for approximately 60% of new cancer cases and 70% of all cancer mortality annually.[1]
Health and functional ability vary more in older adults than in younger patients. Even without the presence of actual disease, aging itself causes gradual, progressive loss in the biologic reserve necessary for the body to maintain physiologic homeostasis under stress, a phenomenon called “homeostenosis.” Even in healthy and highly functioning older adults, there is some degree of loss in the ability to tolerate stress. In addition, many older adults have one or more chronic medical conditions, which further decrease their organs' reserve and ability to respond to stress. Over time, increasing homeostenosis contributes to a gradual but progressive decline in the ability to function in the environment and to tolerate illness and disease.
In the general geriatric population, functional status and level of dependency have been found to predict survival.[2] For the older adult with cancer, then, the oncologist must be able to stage not only the cancer but also consider how a patient's functional status may affect the ability to tolerate and respond to treatment.[3] To accommodate this variable homeostenosis in older patients with cancer and increase their chances for survival, treatment plans need to be more individualized than for the younger population.
Many oncologists use the Karnofsky performance status score (KPS) or Eastern Cooperative Oncology Group (ECOG) scale to assess a patient's ability to perform daily tasks. However, with older patients, these scales often miss subtle degrees of functional impairment.[4] While about 80% of older adults with cancer have an ECOG performance status of 0 or 1 at the time of diagnosis, more than 50% of these patients require assistance with instrumental activities of daily living such as driving, shopping, and managing finances.[5] This functional dependence can have a negative impact on treatment tolerance and survival.[6] For the older adult with cancer, a broader assessment of function is needed.
Geriatricians use standardized assessment tools to distinguish clinical functional age from chronologic age; this is referred to as a comprehensive geriatric assessment (CGA). In the older adult with cancer, the goal of such an assessment would be to identify subtle functional issues that might contribute to morbidity and mortality independent of cancer therapy.
This article identifies some of the tools utilized by geriatricians in assessing the functional status of older adults. We also review the literature that supports the validity of these tools in the general geriatric population and, if available, in the geriatric oncology population. With these tools, oncologists could identify problems that, if modified, would potentially improve the older adult's ability to tolerate treatment.
| Table 1 | ||
Measures for Assessing Physical Function in the Geriatric Population | ||
Self-Report Tools | Domains Assessed | Predicted Clinical Outcome |
IADLs | Telephone use, transportation, shopping, meal preparation, housework, taking medications, handling finances | Impairment in < 1 increases the odds of nursing home placement or mortality 7-fold at 6 yr of follow-up.[8] |
ADLs | Ambulation, bathing, dressing, toileting, transfer from bed to chair, continence, feeding | Impairment in 1 or 2 ADLs increases the odds of nursing home placement 10-fold or mortality 9-fold at 6 yr of follow-up.[8] |
Stair climbing | Ability to climb flight of stairs | Having difficulty increases risk of mortality 3-fold at 2 yr.[64] |
Walking | Ability to walk several blocks | Having difficulty increases risk of mortality 4-fold at 2 yr.[64] |
Performance-Based Tools | ||
Gait speed, 4 m | Decline of 0.1 m/s from baseline at 1 yr increases the 5-yr risk of mortality by 2.23 times.[17] | |
Gait speed, 400 m | Participants in the poorest quartile of functional capacity (> 362 s) had a 3-fold increased risk of death at 5 yr of follow-up compared with those in the best quartile (< 290 s).[65] | |
Get Up and Go test | Sit in a chair with arms folded across the chest, stand, walk forward 3 m, turn, walk back to chair, sit, all without using arms for support. | Subjects needing > 30 s were dependent in transfers and needed assistance to climb stairs.[15] |
SPPB | Walk 8 ft at usual walking speed, rise from straight chair 5 times as quickly as possible, side by side stand for 10 s, semitandem stand for 10 s, and full-tandem stand for 10 s. | Scores of 4–6 were 3.2–7.4 times more likely to reflect ADL impairment; scores of 7–9 were 1.4–3.3 times more likely to reflect ADL impairment.[13] Those with decline of 1 point from baseline at 1 yr were 1.8 times more likely to die within 5 yr.[17] |
ADLs = activities of daily living; IADLs = instrumental activities of daily living; m = meters; s = seconds; SPPB = Short Physical Performance Battery. | ||
