Effect of Postoperative Muscle Loss After Resection of Non-small Cell Lung Cancer on Surgical Outcomes

Background/Aim: Preoperative depletion of psoas muscle mass index (PMI) in lung cancer patients is an unfavorable prognostic factor. The relationship between post-surgical changes in PMI and survival is not clear. Therefore, we conducted a retrospective study to clarify the prognostic significance of preoperative and postoperative PMI changes. Patients and Methods: We retrospectively reviewed lung cancer patients, who underwent curative surgical resection with lymph node dissection and computed tomography (CT) approximately six months post-surgery between 2010 and 2019. Pre-and postoperative PMI was measured from CT images at the third lumbar vertebra level. A sex-dependent PMI change ratio (postoperative PMI/preoperative PMI) was used to divide patients into two groups: high PMI loss (67 patients, <= 25th lower quartile) and low PMI loss/PMI increase (204 patients, >25th lower quartile), and clinicopathological features were compared. Results: Age >= 70 years, elevated preoperative carcinoembryonic antigen levels, advanced pathological stage, lymphatic permeation, vascular invasion, performance of adjuvant platinum-doublet chemotherapy, low body mass index, and postoperative recurrence were significantly higher in the high PMI loss group. Logistic regression analysis found that Charlson comorbidity index, low body mass index, advanced pathological stage, and postoperative recurrence were associated with high PMI loss. The five-year postoperative overall survival rate was 50% in the high PMI loss group and 79% in the low PMI loss/PMI increase group (p<0.001). High PMI loss was also an unfavorable factor in a multivariable Cox's proportional hazard model (p=0.002). Conclusion: Postoperative muscle loss was an independent prognostic factor for poorer overall survival regardless of preoperative sarcopenia, in non-small cell lung cancer.