Clinical significance of left tracheobronchial lymph node dissection in thoracic esophageal squamous cell carcinoma

Objective: The left tracheobronchial lymph nodes are considered as regional lymph nodes for esophageal squamous cell carcinoma, but routine prophylactic left tracheobronchial lymph node dissection for all resectable esophageal squamous cell carcinoma has been controversial. This study aimed to evaluate the prognostic impact of left tracheobronchial lymph node dissection and left tracheobronchial lymph node metastases in thoracic esophageal squamous cell carcinoma and to analyze the risk factors of left tracheobronchial lymph node metastases. Methods: A total of 3522 patients with esophageal squamous cell carcinoma undergoing esophagectomy were included. Overall survival was calculated by a Kaplan-Meier method and compared using the log-rank test. Propensity score matching was conducted to adjust confounding factors. Univariable and multivariable logistic regression analyses were used to identify independent risk factors of left tracheobronchial lymph node metastases. Results: In this study, 608 patients underwent left tracheobronchial lymph node dissection and 45 patients had left tracheobronchial lymph node metastases (7.4%). After propensity score matching, the 5-year overall survival in patients receiving left tracheobronchial lymph node dissection was better than in patients who did not (68.2% vs 64.6%, P = .012). In patients receiving left tracheobronchial lymph node dissection, patients with left tracheobronchial lymph node metastases had a significantly poorer survival than patients without (5-year overall survival: 40.5% vs 62.2%, P = .029). Multivariable logistic analyses showed that clinical T stage and tumor differentiation were independent risk factors for left tracheobronchial lymph node metastases. Conclusions: In thoracic esophageal squamous cell carcinoma, station left tracheobronchial lymph node metastases indicate a poor prognosis and left tracheobronchial lymph nodes dissection seems to be associated with a more favorable prognosis. Clinical T stage and tumor differentiation were independent risk factors for left tracheobronchial lymph node metastases. For patients with high risk, routine prophylactic left tracheobronchial lymph node dissection should be performed.