Respiratory strength and pectoralis muscle mass as measures of sarcopenia: Relation to outcomes in resected non-small cell lung cancer

Abstract

Objectives: Physical biomarkers to stratify patients with lung cancer into subtypes predictive of outcome beyond tumor-related characteristics are underexplored. This study was designed to investigate the clinical utility of preoperative sarcopenia based on respiratory strength and pectoralis muscle mass to predict the risk of death.

Methods: This retrospective study included 346 consecutive patients undergoing curative-intent resection of non-small cell lung cancer from 2009 to 2013. Respiratory strength and muscle mass were assessed by peak expiratory flow rate and pectoralis muscle index (pectoralis muscle area/body mass index) using preoperative spirometry and chest axial images, respectively. Sarcopenia cutoff points were defined by gender-specific medians of peak expiratory flow rates and pectoralis muscle indices. Survival was compared between patients with sarcopenia and patients without.

Results: Sarcopenia was present in 98 patients (28.3%) and was significantly associated with advancing age (P < .001). Patients with sarcopenia exhibited worse 5-year overall survival compared with patients without sarcopenia (69.9% vs 87.2%, P < .001). Multivariate analysis revealed that sarcopenia was an independent adverse prognostic factor (hazard ratio, 1.88; 95% confidence interval, 1.09-3.24; P = .023) after adjustment for gender, age, smoking status, coronary heart disease, diffusing capacity for carbon monoxide, neutrophil-to-lymphocyte ratio, albumin, histologic type, and pathologic stage.

Conclusions: Preoperative sarcopenia as identified by the criteria of low respiratory strength and reduced pectoralis muscle mass is significantly associated with poor overall survival. This may help to develop more individualized management strategies and optimize longitudinal care for patients.

Keywords: non–small cell lung cancer; peak expiratory flow rate; pectoralis muscle; prognosis; sarcopenia.