The number of lymph node dissections related to survival of patients with locally advanced esophageal squamous cell carcinoma after neoadjuvant therapy: A single-center study.

e16009 Background: The number of lymph node dissection (LND) in locally advanced esophageal squamous cell carcinoma (ESCC) after neoadjuvant therapy remains controversial. This study aimed to clarify the relationship between the number of LND and left tracheobronchial lymph node (106tbL) dissection and the survival in these patients, and determine the optimal threshold of the number of dissected lymph nodes. Methods: Patients with locally advanced ESCC after neoadjuvant therapy were included in this study between January 1, 2017 and December 31, 2023. All the patients received minimally invasive McKeown esophagectomy. The postoperative follow-up was carried out every three or six months until death or August 31, 2024. The Kaplan-Meier method and log-rank test were used for univariate analysis, while the Cox proportional hazard model was used for multivariate analysis. Results: A total of 162 patients were included in this study. The median follow-up time was 36.5 months. Five-year overall survival (OS) and disease-free survival (DFS) with the number of LND more than 45 but not more than 60 (45 < LND ≤ 60) were significantly better than those with fewer LND (LND ≤ 45, OS: 73.0% vs 48.5%, P = 0.017; DFS: 72.0% vs 54.1%, P = 0.026) or more (LND > 60, OS: 73.0% vs 36.0%, P = 0.010; DFS: 72.0% vs 33.0%, P = 0.003) . The five-year OS with more thoracic LND was significantly better (> 30 vs ≤ 30: 73.2% vs 46.7%, P = 0.018), and the five-year DFS had a better trend (> 30 vs ≤ 30: 65.2% vs 54.4%, P = 0.134), but not statistically significant. Multivariate analysis showed better OS with a higher number of thoracic LND (HR, 0.317; 95% CI, 0.154-0.650; P = 0.002；Table 1), and better DFS with a total number of LND more than 45 but not more than 60 (HR, 0.373; 95% CI, 0.182-0.765; P = 0.007). The 106tbL lymph node metastasis rate was 6.8% (10/147). The patients with 106tbL metastasis had worse OS and DFS. Fewer or no dissecting of 106tbL reduced five-year DFS (< 5 vs ≥ 5: 49.5% vs 68.8%, P = 0.056), but the difference was of borderline significance. Conclusions: The number of lymph node dissection is related to the OS and DFS in locally advanced ESCC patients after neoadjuvant therapy. The number of LND between 45 and 60, and the number of thoracic LND more than 30 are recommended, which may improve survival and local disease control. The 106tbL lymph node metastasis is related to poor prognosis and patients may benefit from more 106tbL lymph node dissection. Univariate and multivariate Cox regression analysis of factors for OS. Variables Univariate Analysis Multivariate Analysis HR (95% CI) P HR (95% CI) P ypN stage < 0.001 N0 Reference Reference N1 3.392 (1.496-7.689) 0.003 4.049 (1.773-9.248) 0.001 N2 4.469 (1.902-10.498) 0.001 5.105 (2.169-12.017) < 0.001 N3 6.283 (2.227-17.727) 0.001 8.877 (3.100-25.419) < 0.001 Thoracic LND ≤ 30 Reference Reference > 30 0.428 (0.211-0.867) 0.019 0.317 (0.154-0.650) 0.002 Abbreviations: OS, overall survival; HR, hazard ratio; CI, confidence interval; LND, lymph node dissection; 106tbL, left tracheobronchial lymph node.