Estimating survival time in older adults receiving chemotherapy for advanced cancer

Abstract

PurposeWe determined the accuracy of oncologists' estimates of expected survival time (EST) for older adults with advanced cancer, and explored predictors of survival from a geriatric assessment (GA). MethodsPatients aged ≥65 years starting a new line of palliative chemotherapy were eligible. For each patient at enrolment, oncologists estimated EST and rated frailty (Canadian Study on Health and Aging Clinical Frailty Scale, 1 = very fit, to 7 = severely frail), and a researcher completed a GA. We anticipated estimates of EST to be: imprecise [<33% between 0.67 and 1.33 times the observed survival time (OST)]; unbiased (approximately 50% of participants living longer than their EST); and, useful for estimating individualised worst-case (10% living ≤¼ times their EST), typical (50% living half to double EST), and best-case (10% living ≥3 times EST) scenarios for survival time. Logistic regression was used to identify independent predictors of OST. ResultsThe 102 participants [median age 74 years, vulnerable to frail (4–7 on scale) 35%] had a median OST of 15 months. 30% of estimates of EST were within 0.67–1.33 times the OST. 54% of participants lived longer than their EST, 9% lived ≤1/4 of their EST and 56% lived half to double their EST. Follow-up was insufficient to observe those living ≥3 times their EST. Independent predictors of OST were frailty (HR 4.16, p < .0001) and cancer type (p = .003). ConclusionsOncologists' estimates of EST were imprecise, but unbiased and accurate for formulating scenarios for survival. A pragmatic frailty rating was identified as a potentially useful predictor of OST.