Estimating Survival Time in Older Adults Receiving Chemotherapy for Advanced Cancer

Purpose: We 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).

Methods: Patients 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.

Results: The 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).

Conclusions: Oncologists' 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.