Survival impact of the number of lymph nodes dissection in patients receiving neoadjuvant chemotherapy for esophageal squamous cell carcinoma

This study aimed to investigate the survival impact of the number of lymph nodes dissection (LND) in patients receiving neoadjuvant chemotherapy (NCT) for esophageal squamous cell carcinoma (ESCC). We retrospectively analyzed the clinical pathological data and survival of 407 ESCC patients who underwent esophagectomy after NCT between January 2015 and December 2016. The relationship between the number of LNDs and 5-year overall survival (OS) or disease-free survival (DFS) was plotted by using restricted cubic spline analysis. A Cox proportional hazards regression model was used to identify prognostic factors of OS and DFS. We observed an obvious non-linear relationship between LND and the hazard ratios (HRs) for OS (P = 0.0015) and DFS (P < 0.001) of all the patients. In the multivariate analysis of OS and DFS, the number of LNDs (greater than 28 and less than 46) had a significant protective effect on survival (OS: HR: 0.61, 95% CI: 0.42-0.88, P = 0.007; DFS: HR: 0.50, 95% CI: 0.36-0.70, P < 0.001). For patients with nodal metastases, it was also an independent prognostic factor for OS (HR, 0.56, 95% CI, 0.35-0.90, P = 0.017) and DFS (HR, 0.42, 95% CI, 0.28-0.65, P < 0.001). Some degree of lymphadenectomy after NCT was beneficial in improving 5-year OS and DFS for ESCC patients with nodal metastases. For patients with nodal negativity, more extended lymphadenectomy did not improve patient survival.