ASO Visual Abstract: Nutritional Outcomes of Thoracic Duct Resection for Radical Esophagectomy by Assessment of Body Composition Changes in 1 Year: A Single-Center Retrospective Study

Background. Thoracic duct (TD) resection is performed when the tumor or a metastatic lymph node directly invades the TD, and is sometimes indicated for radical lymphadenectomy during esophagectomy in esophageal cancer patients. However, the effect of TD resection on nutritional status has not been established. Patients and Methods. In total, 174 consecutive patients from October 2015 to March 2019 who underwent radical esophagectomy for esophageal cancer in Toranomon Hospital were classified into thoracic duct preserved group (n = 51) and TD-resected (TD-R) group (n = 123). We compared laboratory data, body composition data from bioelectrical impedance analysis measured preoperatively and at 1 and 12 months after surgery, and postoperative complications between the two groups. Results. Clinical stage was significantly more advanced in the TD-R group. Total body weight, body mass index, and fat mass continuously decreased in the two groups over 12 months after surgery, and the decreases were statistically greater in the TD-R group at 12 months after surgery. Skeletal muscle mass and fat-free mass decreased over 1 month after surgery and stayed in a reduced state until 12 months after surgery without statistically significant differences between the two groups. TD resection did not increase incidence of postoperative complications (Clavien-Dindo classification C grade III), but TD resection increased incidence of chylothorax. Conclusions. Our results suggest that loss of body fat mass, which was a main contributor to body weight loss, was accelerated in the TD-R group, but TD resection does not deteriorate loss of muscle mass at 12 months after surgery.