Prognostic Impact of Postoperative Skeletal Muscle Decrease in Non-Small Cell Lung Cancer.

Background. Preoperative skeletal muscle loss was reported to be associated with a postoperative poor prognosis in non-small cell lung cancer (NSCLC) patients. The aim of this study was to elucidate the relationship between the change in skeletal muscle mass after surgery and the postoperative outcomes in NSCLC patients. Methods. The data were analyzed for 204 NSCLC patients who had undergone curative lung resection and whose preoperative and postoperative (1-year) computed tomographic images were available. The skeletal muscle area (SMA) at the 12th thoracic vertebra level was used. Postoperative/preoperative ratio was defined as postoperative normalized SMA (cm(2)/m(2)) divided by preoperative normalized SMA. The cutoff value was set to a postoperative/preoperative ratio of 0.9. The neutrophil-lymphocyte ratio, the platelet-lymphocyte ratio, modified Glasgow prognostic score, and prognostic nutritional index were used to estimate change in the nutritional status. Results. There were 70 patients (34.3%) classified into the SMA-decreased group. Low body mass index was significantly associated with the SMA-decreased patients (P = .019). The SMA-decreased status was an independent prognostic factor for poor overall survival (P < .001) and disease-free survival (P = .001). The SMA-decreased status was significantly associated with the postoperative exacerbation of the neutrophil-lymphocyte ratio (P = .009), platelet-lymphocyte ratio (P = .026), modified Glasgow prognostic score (P = .003), and prognostic nutritional index (P = .013). Conclusions. Skeletal muscle loss after surgery is significantly associated with poor postoperative outcomes in NSCLC patients. Further studies investigating the clinical impact of postoperative nutritional intervention are needed. (C) 2020 by The Society of Thoracic Surgeons