Risk factors for progressive sarcopenia 6 months after complete resection of lung cancer: what can thoracic surgeons do against sarcopenia?

Background: Our previous report described how postoperative progression of sarcopenia predicted long-term prognosis after complete resection of non-small cell lung cancer (NSCLC) in heavy smokers. However, there are currently no effective means to treat progressive sarcopenia. In this study, we aimed to confirm our previous findings in a larger population and to identify factors associated with postoperative progression of sarcopenia to propose possible preventative measures. Methods: This retrospective study analyzed the data of 1,095 patients who underwent curative lobar resection for NSCLC at Kanagawa Cancer Center. We divided patients into four groups according to sex and Brinkman index (BI) above or below 600. Six-month postoperative changes in the skeletal muscle index (SMI) were calculated and associations between clinicopathological factors including changes in SMI and mortality from postoperative 6 months were examined. Only in groups in which postoperative depletion of SMI was shown to be associated with the prognosis, we identified clinicopathological factors associated with depletive SMI. Results: The overall survival rates of 1,095 patients were 89.8% and 82.5% at 3 and 5 years, respectively. The median 6-month change in SMI was -3.4% (range, -22.3% to +17.9%). Multivariate analysis revealed that poor prognosis was independently predicted by a large reduction in the SMI (cut-off value: -10%) in males with a BI >= 600. In 391 heavy-smoking males, factors associated with a postoperative change in SMI <=-10% were history of other cancers (including gastric cancer) low forced expiratory volume in one second (FEV 1.0, cut-off value: 1,870 mL), and prolonged operation time (cut-off value: 200 minutes). Conclusions: Perioperative measures to prevent postoperative sarcopenia are appropriate for heavy smokers. We obtained some clues regarding countermeasures, one of which may be avoiding long-time operation. Further studies including clinical trials to assess perioperative anti-sarcopenia treatments, are needed.