Long-term variation in skeletal muscle and adiposity in patients undergoing esophagectomy

This study seeks to define long-term variation in body composition in patients undergoing esophagectomy for cancer and to associate those changes with survival. Assessment of skeletal muscle, visceral (VAT) and subcutaneous adipose tissue (SAT) was performed using computed tomography (CT) images routinely acquired: at diagnosis; after neoadjuvant therapy, and; >6 months after esophagectomy. In cases where multiple CT scans were performed >6 months after surgery, all available images were assessed. Ninty-seven patients met inclusion criteria with a median of 2 (range 1-10) postoperative CT images acquired between 0.5 and 9.7 years after surgery. Following surgical treatment of esophageal cancer, patients lost on average 13.3% of their skeletal muscle, 64.5% of their VAT and 44.2% of their SAT. Sarcopenia at diagnosis was not associated with worse overall survival (66.3% vs. 68.5%; P = 0.331). Sarcopenia 1 year after esophagectomy was however associated with lower 5-year overall survival (53.8% vs. 87.5%; P = 0.019). Survival was lower in those patients who had >10% decrease in skeletal muscle index (SMI; 33.3% vs. 72.1%; P = 0.003) and >40% decrease in SAT 1 year after surgery (40.4% vs. 67.4%; P = 0.015). On multivariate analysis, a decline in SMI 1 year after surgery was predictive of worse survival (HR 0.38, 95%CI 0.20-0.73; P = 0.004). This study provides new insight relating to long-term variation in body composition in patients undergoing esophagectomy for cancer. Findings provide further evidence of the importance of body composition, in particular depletion of skeletal muscle, in predicting survival following esophagectomy.