Low muscularity increases the risk for post-operative pneumonia and delays recovery from complications after oesophago-gastric cancer resection.

Background Low muscularity is associated with adverse surgical outcomes. We aimed to determine whether low muscularity is associated with an increased risk of post-operative complications and reduced long-term survival after oesophago-gastric cancer surgery. Methods Patients who underwent radical oesophago-gastric cancer surgery with preoperative abdominal computed tomography (CT) imaging were included. Low skeletal muscle index (SMI), measured by CT, was determined using pre-defined cut-points. Oncological, surgical, complications and outcome data were obtained from a prospective database. Results Of 108 patients, 61% (n = 66) had low SMI preoperatively. Patients with low SMI had a higher rate of post-operative pneumonia (30 vs. 7% normal muscularity, P = 0.004). Median length of stay (LOS) was higher in patients with low SMI if they had any complication (19.5 vs. 14 days, P = 0.026) or pneumonia (21 vs. 13 days, P = 0.018). On multivariate analysis, low SMI (OR 3.85, CI 1.10-13.4, P = 0.025), preoperative weight loss (OR 1.13, CI 1.01-1.25, P = 0.027), and smoking (OR 5.08, CI 1.24-20.9, P = 0.024) were independent predictors of having a severe complication. There was no difference in 5-year overall (62% vs. 69%, P = 0.241) and disease-free (11% vs. 21.4%, P = 0.110) survival between low SMI and normal muscle mass groups. Conclusion Low SMI is associated with a significantly increased risk of pneumonia and increased LOS for patients with complications. Assessment of muscle mass may require additional muscle quality, strength, and physical performance measures to enhance preoperative risk assessment.