Use of Comprehensive Geriatric Assessment in Oncology Patients to Guide Treatment Decisions and Predict Chemotherapy Toxicity
Purpose: Our objective was to review the utility of pretreatment comprehensive geriatric assessment (CGA) and its impact on decision making regarding choice and intensity of oncologic therapeutic regimens for older, frail, or poor-functional-status patients, as well as using this prospective assessment to predict chemotherapy-related toxicities. Database searches were conducted in Medline, PubMed, and Ovid for clinical studies, review articles, and journal publications. Search terms included geriatric assessment , medical oncology , chemotherapy , frailty , toxicity , and functional status . Thirty-seven pertinent articles were retrieved and serve as the basis for this clinical review.
Observations: CGA is an important tool for examining aspects of frailty and functional status that are not captured by traditional performance status measures. These findings may then be used in selection of appropriate therapeutic regimens for a given patient that are efficacious and tolerable. Such pretreatment assessments also have been used in predicting therapy-related toxicities.
Conclusions: Frail and older patients are common in oncology practices and are at high risk for therapy-related toxicities because of comorbidities and physiologic changes, presenting a considerable clinical challenge. CGA establishes evidence-based strategies to better assess the functional status of such patients and is predictive for chemotherapy-related toxicities in this vulnerable group. Despite publications on these measures in the oncology literature, there is limited evidence-based research to demonstrate the utility of CGA by practicing oncology providers and how to implement it into practice.
The Charlson Comorbidity Index was originally designed to predict 1-year mortality on the basis of a weighted composite score for the following categories: cardiovascular, endocrine, pulmonary, neurologic, renal, hepatic, gastrointestinal, and neoplastic disease.13 It is now the most widely used comorbidity index and has been adapted and verified as applicable and valid for predicting the outcomes and risk of death from many comorbid diseases.14 The Cumulative Illness Rating Scale has been validated as a predictor for readmission for hospitalized older adults, hospitalization within 1 year in a residential setting, and long-term mortality when assessed in inpatient and residential settings.15
Polypharmacy
Polypharmacy (use of ≥ 5 medications) is common in older patients regardless of cancer diagnosis and is often instead defined as “the use of multiple drugs or more than are medically necessary.”16 The use of multiple medications, including those not indicated for existing medical conditions (such as over‐the‐counter, herbal, and complementary/alternative medicines, which patients often fail to declare to their specialist, doctor, or pharmacist) adds to the potential negative aspects of polypharmacy that affect older patients.17
Patients with cancer usually are prescribed an extensive number of medicines, both for the disease and for supportive care, which can increase the chance of drug-drug interactions and adverse reactions.18 While these issues certainly affect quality of life, they also may influence chemotherapy treatment and potentially impact survival. Studies have shown that the presence of polypharmacy has been associated with higher numbers of comorbidities, increased use of inappropriate medications, poor performance status, decline in functional status, and poor survival.18
Functional Status
Although Eastern Cooperative Oncology Group (ECOG) performance status and Karnofsky Performance Status are commonly used by oncologists, these guidelines are limited in focus and do not reliably measure functional status in older patients. Functional status is determined by the ability to perform daily acts of self-care, which includes assessment of activities of daily living (ADLs) and instrumental activities of daily living (IADLs). ADLs refer to such tasks as bathing, dressing, eating, mobility, balance, and toileting.19 IADLs include the ability to perform activities required to live within a community and include shopping, transportation, managing finances, medication management, cooking, and cleaning.11
Physical functionality also can be assessed by measures such as gait speed, grip strength, balance, and lower extremity strength. These are more sensitive and shown to be associated with worse clinical outcomes.20 Grip strength and gait speed, as assessed by the Timed Up and Go test or the Short Physical Performance Battery measure strength and balance.12 Reduction in gait speed and/or grip strength are associated with adverse clinical outcomes and increased risk of mortality.21 Patients with cancer who have difficulty with ADLs are at increased risk for falls, which can limit their functional independence, compromise cancer therapy, and increase the risk of chemotherapy toxicities.11 Impaired hearing and poor vision are added factors that can be barriers to cancer treatment.
Cognition
Cognitive impairment in patients with cancer is becoming more of an issue for oncology HCPs as both cancer and cognitive decline are more common with advancing age. Cognition in cancer patients is important for understanding their diagnosis, prognosis, treatment options, and adherence. Impaired cognition can affect decision making regarding treatment options and administration. Cognition can be assessed through validated screening tools such as the Mini-Mental State Examination and Mini-Cog.11
