Loss of Muscle Mass Is a Novel Predictor of Postoperative Early Recurrence in N2-Positive Non-Small-Cell Lung Cancer

Background: We often experienced early recurrence in patients with completely resected N2-positive non-small-cell lung cancer (NSCLC). Loss of muscle mass is a poor prognostic factor in patients with several stages of NSCLC. This study aimed to investigate the relationship between preoperative loss of muscle mass and postoperative early recurrence in patients with N2-positive NSCLC. Methods: We retrospectively analyzed 47 male patients with completely resected pathological N2-positive NSCLC. Early recurrence was defined as that diagnosed within 1 year after the operation. We used the L3 muscle index (cross-sectional area of muscle at the L3 level, normalized for height) as a clinical measurement of loss of muscle mass (cutoff value, 52.4 cm(2)/m(2)). Results: In all, 18 patients with early recurrence had significantly poorer outcomes compared with those without (P <0.01). In univariate analysis, loss of muscle mass (P = 0.023), carcinoembryonic antigen (CEA) level >5.0 ng/mL (P = 0.002), and absence of postoperative chemotherapy (P = 0.042) were predictors of postoperative early recurrence. In multivariate analysis, loss of muscle mass (P = 0.004) and CEA level >5.0 ng/mL (P = 0.001) were independent predictors. Conclusions: Loss of muscle mass is an independent predictor of postoperative early recurrence in pathological N2-positive NSCLC patients.