A Society of Thoracic Surgeons General Thoracic Surgery Database Analysis of the Association Between Lymph Node Dissection and Chylothorax

BACKGROUND: Guideline-concordant lymph node (LN) dissection may increase chylothorax risk after lung resection. We analyzed predictors of chylothorax, with a focus on the extent and pattern of LN dissection, using The Society of Thoracic Surgeons General Thoracic Surgery Database. METHODS: We studied patients who underwent elective lung resection for stage I to III non-small cell lung cancer from January 2015 to December 2024 (N = 152,823). The primary end point was 30-day postoperative chylothorax. Independent predictors of chylothorax were identified using multivariable logistic regression. A sensitivity analysis assessed nodal stations and chylothorax using contemporary data (2021-present). RESULTS: The overall incidence of chylothorax was 0.73% (n = 1110). Patients with chylothorax were younger, had fewer comorbidities, a higher frequency of right-sided tumors (78.4% vs 60.9%), and more advanced disease. The median number of LNs dissected was higher in the chylothorax group (14 [interquartile range, 9-21] vs 10 [interquartile range, 6-16]). The strongest independent predictors of chylothorax included the number of sampled LNs, cT4 (adjusted odds ratio [aOR], 4.72; 95% CI, 1.13-19.63), right-sided tumor (aOR, 2.17; 95% CI, 1.83-2.59), dialysis (aOR, 2.15; 95% CI, 1.49-3.11), and open surgical approach (aOR, 1.59; 95% CI, 1.34-1.88). Sensitivity analyses confirmed these findings and identified 2R sampling as an additional independent predictor (aOR, 1.27; 95% CI, 1.02-1.57). Chylothorax was associated with a higher rate of major morbidity (35.7% vs 6.6%, P < .001) but not increased mortality (1.4% vs 1.0%, P = .17). CONCLUSIONS: Chylothorax risk increases with the number of LNs dissected and is associated with a dramatic increase in morbidity but not mortality. This underscores the importance of balancing the oncologic benefit of extensive LN dissection in patients with low-grade cancers against the risks it poses, including chylothorax.