Clinical Impact and Risk Factors for Skeletal Muscle Loss After Complete Resection of Early Non-small Cell Lung Cancer

Background: A relationship between sarcopenia diagnosed by skeletal muscle area (SMA) and poor prognosis in cancer patients has recently been reported. This study aimed to clarify the clinical significance of postoperatively decreased SMA in patients with early non-small cell lung cancer (NSCLC). Methods: This study selected 101 patients with pathologic stage 1 NSCLC who had undergone pre- and postoperative (~ 1 year) computed tomography scans and lobectomy between 2005 and 2010 at Kyushu University Hospital. The post/pre ratio was defined as the postoperative normalized SMA (cm²/m²) at the 12th thoracic vertebra level divided by the preoperative normalized SMA. The cutoff value for the post/pre ratio was set at 0.9. Results: The study classified 31 patients (30.7%) as having decreased SMA. Poor performance status (PS) was significantly associated with decreased SMA (p = 0.048). The patients with decreased SMA had a significantly shorter disease-free survival (DFS) (p < 0.001) and overall survival (OS) (p < 0.001) than the other patients. Decreased SMA was found to be an independent prognostic factor for DFS (p = 0.010) and OS (p = 0.0072). The independent risk factors for skeletal muscle loss included poor PS (PS ≥ 1) and obstructive ventilatory impairment [forced expiratory volume (FEV) 1% < 70%]. Conclusions: Skeletal muscle loss after surgery is significantly associated with postoperative poor outcomes for patients with early NSCLC. Patients with poor PS, obstructive ventilatory impairment, or both need careful support to maintain their skeletal muscle mass. Future prospective studies may clarify whether physical activity and nutritional support improve postoperative prognosis.