Sarcopenia is an independent unfavorable prognostic factor of non-small cell lung cancer after surgical resection: A comprehensive systematic review and meta-analysis

Background Whether sarcopenia has any impact on long-term survival of patients with surgically treated non-small cell lung cancer (NSCLC) remains unclear. We conducted a meta-analysis focusing on current topic comprehensively for the first time. Methods We systematically searched relevant studies in PubMed, Embase, and Cochrane Library up to July 3, 2018. Data of 5-year overall survival (OS) and disease-free survival (DFS) rates as well as hazard ratio (HR) of OS were collected for analysis by using the STATA 12.0 package. Results A total of 6 cohort studies consisting of 1213 patients (422 patients with sarcopenia and 791 patients without) were included for analysis. Meta-analysis showed that patients with sarcopenia had a significantly lower 5-year OS rate (risk ratio (RR) = 1.63; 95% confidence interval (CI) = [1.13, 2.33]; P = 0.008) than those without, which was more prominent in patients with early-stage NSCLC. Sarcopenia was found to be an independent predictor of poor OS in patients with surgically treated NSCLC (HR = 2.85; 95%CI = [1.67, 4.86]; P < 0.001). With a limited sample size, there was no sufficient evidence of significantly different 5-year DFS rate between the two groups (RR = 1.14; 95%CI = [0.59, 2.17]; P = 0.70). However, in the subgroup of patients with early-stage NSCLC, sarcopenia was associated with a significantly lower 5-year DFS rate (RR = 1.59; 95%CI = [1.01, 2.52]; P = 0.046). Conclusion Patients with sarcopenia had a significantly worse prognosis than those without after surgical resection of NSCLC especially in those at early stage. Sarcopenia is an independent unfavorable prognostic factor for patients with surgically treated NSCLC. (246 words).