Extracellular Water-to-total Body Water Ratio as an Objective Biomarker for Frailty in Lung Cancer Patients

Abstract

Background/aim: Our previous study revealed the association between extracellular water-to-total body water ratio (ECW/TBW) and the therapeutic durability of chemotherapy and/or immune checkpoint inhibitors in advanced lung cancer. We retrospectively examined the usefulness of ECW/TBW in detecting frailty compared to other bioelectrical impedance (BIA) parameters in a larger number of patients.

Patients and methods: Lung cancer patients underwent BIA before anti-cancer therapy at our hospital between June 1, 2018 and July 31, 2020.

Results: Of 99 patients, 26 were assigned to ECW/TBW≥0.4 (higher group: HG) and 57 to ECW/TBW<0.4 (lower group: LG). ECW/TBW increased significantly with performance deterioration and ageing. HG patients had significantly shorter time-to-treatment failure (TTF) than LG patients. In patients with performance status 0-1, those in the HG had shorter TTF than those in the LG. ECW/TBW was the only independent predictor of TTF according to multivariate analysis.

Conclusion: ECW/TBW is an objective biomarker for detecting frailty among lung cancer patients.

Keywords: Lung cancer; bioelectrical impedance analysis; frailty; ratio of extracellular water to total body water; time to treatment failure.