Low muscle density on chest computed tomography is associated with early death in non–small cell lung cancer

The aim of this study was to investigate the association of trunk muscle properties derived from chest computed tomography (CT) with worse posttreatment survival at different follow-up time intervals in patients with non–small cell lung cancer (NSCLC). This retrospective study included patients with NSCLC who underwent curative resection and postoperative chest CT between March 2020 and April 2021. Cross-sectional area and density of the trunk muscles were measured on CT at the level of the first lumbar vertebra. Cox proportional-hazards models were used to predict worse posttreatment survival risk at different follow-up time intervals adjusted for age, sex, and body mass index. Area under the receiver operating characteristic curve (AUC) was calculated to evaluate the diagnostic performance. Among 263 patients, 181 died after a median follow-up of 4.1 years. The measured muscle properties were higher in patients who did not die compared with those in patients who died. Patients with high L1 muscle density had lower risks of death within the first year (hazard ratio [HR], 0.58; 95% confidence interval [CI], 0.42–0.80; P < 0.01) and overall (HR, 0.74; 95% CI, 0.63–0.87; P < 0.01). An increase of one standard deviation in L1 muscle density was associated with a 28% lower risk of death after the second year (HR, 0.72; 95% CI, 0.56, 0.93; P = 0.01). The AUC of L1 muscle density for predicting death within the first year was 0.735. There is a time-dependent effect of L1 muscle density on survival in patients with NSCLC. Low L1 muscle density is an important predictor for worse posttreatment survival and is associated with early death.