Combination of Skeletal Muscle Mass and Density Predicts Postoperative Complications and Survival of Patients With Non-Small Cell Lung Cancer.

BACKGROUND: Few studies have assessed the comprehensive skeletal muscle depletion associated with loss of muscle quantity (sarcopenia) and reduced muscle quality in cancer patients. This study aimed to clarify the impact of skeletal muscle depletion on outcomes after non-small cell lung cancer surgery. METHODS: Data for 341 patients with pathologic stages 1 to 3A non-small cell lung cancer who underwent lobectomy and mediastinal lymph node dissection from 2009 to 2013 were retrospectively reviewed. The integrative pectoralis muscle index (IPMI) was assessed by multiplying the normalized pectoralis muscle area (area/body mass index) and mean radiodensity on chest images. Postoperative outcomes were compared among sex-specific quartiles of IPMI. The trend of continuous and categorical variables was analyzed using the Jonckheere-Terpstra test and the Cochrane-Armitage test, respectively. RESULTS: Respiratory strength declined with decreasing quartiles of IPMI (P < 0.001). The risk of major complications escalated with the decrease of IPMI among four quartiles (7.1 %, 16.7 %, 18.4 %, and 22.4 %; P = 0.008). The hospital stay was prolonged for patients with reduced IPMI (P = 0.001). Patients in the lowest and highest quartiles had the worst and best 5-year overall survival, respectively, compared with those in the two intermediate quartiles of IPMI (67.0 %, 87.9 %, and 81.2 %, respectively; P=0.001). Multivariate analysis identified the lowest quartile of IPMI as an independent poor prognostic factor (hazard ratio, 1.88; 95 % confidence interval, 1.11-3.19; P = 0.020). CONCLUSION: Comprehensive skeletal muscle profiling, including morphometric mass and componential density on chest imaging, has the potential to refine risk stratification and prognostication in non-small cell lung cancer.