Impact of Thoracic Duct Resection on Postoperative Body Composition Trajectory After Oesophagectomy: A Prospective...

Thoracic duct resection (TDR) is frequently performed during radical oesophagectomy to improve locoregional control in oesophageal squamous cell carcinoma (ESCC). However, its impact on postoperative body composition-particularly skeletal muscle mass-remains unclear. This study aimed to evaluate the extent and temporal pattern of postoperative changes in adiposity- and sarcopenia-related indices following TDR.

In this prospective cohort study, 347 patients with ESCC who underwent curative oesophagectomy between May 2018 and June 2022 were included. Patients were classified into a TDR group (n = 288) and a thoracic duct preservation group (n = 59). Body composition was assessed using bioelectrical impedance analysis (BIA) at six time points: preoperatively and 1, 2, 3, 6 and 12 months postoperatively, yielding 1925 measurements. Metrics analysed included body mass index (BMI), fat mass index (FMI), skeletal muscle mass index (SMI) and fat-free mass index (FFMI). Sensitivity analysis was performed using 1:1 propensity score matching (PSM), based on key clinical variables.

Median age was 64 years, and ~90% of patients were male in both groups. Baseline operative variables were comparable between groups, including operative time (485 vs. 478 min), total lymph nodes (66 vs. 63) and complication rates (30% vs. 32%). BMI and FMI declined gradually over 12 months with no significant between-group differences (BMI at 12 months: TDR vs. preservation, 21.0 vs. 20.6 kg/m²; p = 0.809). In contrast, SMI and FFMI showed significant early postoperative declines, with more pronounced reductions in the TDR group during the first 3 months (SMI: -11.2% vs. -8.1%, p = 0.036). These early differences attenuated after PSM but remained directionally consistent. Recovery of muscle mass began around postoperative month 3, and by 12 months, sarcopenia-related indices were comparable between groups (SMI: p = 0.343; FFMI: p = 0.733). Subgroup analysis in patients with clinical stage I disease revealed similar patterns, suggesting that the observed muscle loss may reflect procedure-related effects, independent of tumour burden. Exploratory nutritional markers-including albumin, lymphocyte count and cholesterol-showed no significant intergroup differences at any interval.

This is the largest study to date to assess longitudinal body composition changes after TDR using serial BIA. TDR was associated with a greater decline in sarcopenia-related indices, particularly within the first 3 months. These effects were transient, reversible and reproducible in early-stage patients. Our findings support the oncologic role of TDR while underscoring the importance of early nutritional and rehabilitative care.