Frailty involves the impairment of physiologic reserve and ability to maintain homeostasis following a stressor. It is a poor prognostic factor in adults with cancer, but the method used to define frailty has been a moving target.1 In research settings, different definitions used include the phenotypic Fried criteria, a deficit accumulation model defined by a frailty index, or deficits on a comprehensive geriatric assessment.2,3,4 Each of these definitions has integration challenges in a clinical setting. The Modified Frailty Index (mFI) is a brief tool that correlates with post-operative morbidity and mortality in surgical populations.5,6,7
The importance of frailty in patients with metastatic non-small cell lung cancer (NSCLC) receiving chemotherapy remains unclear and the correlation of the mFI with outcomes in this population was unknown. As part of a project exploring patterns of treatment in patients with metastatic NSCLC, we were able assess the mFI through Dr. Mathur’s research at the University of Manitoba BSc Med program and funding from the CancerCare Manitoba Foundation.
We investigated the association of mFI with chemotherapy-related toxicity, progression-free survival (PFS), and overall survival (OS) using a retrospective cohort study design. The mFI has been assessed using prospective surgical databases, but we measured it through retrospective chart review of all 426 patients diagnosed from 2011 to 2016 with metastatic NSCLC who received chemotherapy in the Canadian province of Manitoba. Our retrospective design required merging the typical mFI categories for stroke and transient ischemic attack with or without residual deficits since that information was rarely included in the chart (Table 1). We separated patients into fit (mFI=0), pre-frail (mFI=1-2), and frail (mFI=3+) groups.