Is Karnofsky performance scale a proxy measure of frailty phenotype in older adults with cancer?

Abstract

e24035 Background: The use of performance status (PS) assessments in patients with cancer is a common practice to determine their suitability for treatment, clinical trial enrollment, and prognosis. The Karnofsky Performance Scale (KPS) and Eastern Cooperative Oncology Group Performance Status (ECOG PS) score are widely used clinical instruments for this purpose. However, these tools are subjective and unidimensional, with potential for bias, and were validated in younger patients. KPS has demonstrated greater specificity than ECOG in evaluating PS. Frailty, a dynamic medical syndrome characterized by diminished strength, endurance, and reduced physiological function, is recognized as a predictor of vulnerability to adverse outcomes, especially in older adults with cancer. The Fried Frailty Phenotype (FP) is a widely validated tool that uses both objective and subjective measures to identify frailty based on presence of 3 or more criteria: unintentional weight loss, self-report of exhaustion (fatigue), weakness (measured by grip strength), slow walking speed, and low physical activity. Our study compares physician-rated KPS with FP (fit, prefrail, frail) and looks at correlation of both tools in older adults with cancer. Methods: Data from older adults with solid tumor malignancies referred to the geriatric oncology clinic for geriatric assessment (GA) from January 2015–August 2019 were abstracted. Physician-rated KPS (0-100) were categorized into 3 groups: normal activity, high functioning (80–100); intermediate, capable of self-care but unable to do active work (70); and poor PS, requires considerable assistance (<60). These were compared to FP which classified patients based on the number of frailty criteria present: fit (0), prefrail (1-2), and frail (>3). Frequency data calculation and bivariate analysis were done. Results: 241 older adults with cancer completed a GA, median age of 80 years, 52% female. 57% were frail, 37% prefrail, and 6% fit. 90% of patients with KPS 80-100, had prefrail and frail phenotypes. Patients with KPS 70 had 24% prefrail and 76% frail phenotypes and those with KPS < 60 had 10% prefrail and 90% frail phenotypes. Conclusions: Majority of older patients with prefrail and frail phenotypes were assessed as high functioning (KPS 80-100). KPS is an inadequate substitute for FP and should not be used alone in assessing functional status of older adults with cancer.