Abstract
Background
The possible presence of occult tumor dissemination is the rationale of radical systematic lymphadenectomy. Theoretically, the more extent of lymphadenectomy, the more similar survival outcomes between node-negative and node-positive patients. Accordingly, there will be a certain number of examined lymph nodes (NELN) for patients with only one tumor-positive lymph node that can equal their survival with the node-negative patients, and this cut-off point should be define the minimal requirement for an adequate extent of lymphadenectomy. The aim of this report was to determine the optimal number of examined lymph nodes (NELN) dissection for esophageal squamous cell carcinoma (ESCC) by this novel method.
Methods
We retrospectively reviewed 589 ESCC patients from June 2011 and July 2012. Among them, 372 patients were pathologically confirmed with node-negative (N 0 + ), and 217 patients with only one tumor-positive lymph node (N 1 + ). Comparison of overall survival were performed using the Kaplan-Meier method. Cox regression hazard model was used for multivariate analysis to assess the independent influence of NELN on overall survival.
Results
The median survival for N 0 + and N 1 + patients was 32 versus 23 months (HR 1.61; 95% CI 22.86- 29.148; P = 0.000). Survival analyses revealed that the NELN positively correlated with overall survival (OS) both for patients with N 0- (P = 0.024) and N 1 + (P = 0.046), and an independent prognostic predictor only for N 0 + patients (hazard ratio 0.984; P = 0.032). When the cut-off point of NELN was set as a value less than 18, stratum analysis within the Kaplan–Meier method showed that NELN did not affect the results that N 1 + patients have a worse overall survival as compared with N 0 + patients (P < 0.05). However, stratum analysis showed that no significant difference in OS was observed between N 1 + and N 0 + patients when the NELN was greater than 18.
Conclusion
The NELN should be considered a mandatory requirement for improving the OS of ESCC patients. The minimum of 18 lymph nodes removed for ESCC is rational and should be complied with.
Disclosure
All authors have declared no conflicts of interest.
Identification and Validation of Lymphovascular Invasion as a Prognostic and Staging Factor in Node-Negative Esophageal Squamous Cell Carcinoma