Background: The number of negative lymph nodes (NLNs) can be used for predicting clinical outcomes for patients with esophageal carcinoma as it is believed to reflect the extent of lymphadenectomy. However, when patients are treated with the same surgical procedure, its prognostic value is not clear.
Methods: We reviewed the records of 332 patients with thoracic esophageal squamous cell carcinoma (ESCC) who underwent three-field lymphadenectomy (3FLND) and had at least 15 lymph nodes removed. We used Kaplan-Meier estimates to compute overall survival (OS), the log-rank tests to assess the equality of survival rates, and Cox regression analyses to evaluate the association between survival and NLN count after adjusting for potential confounders.
Results: At a median follow-up interval of 36 months, the median OS was 47 months and the 5-year survival rate was 47.0 %. NLN count was independently associated with OS, and higher numbers of NLNs were linked to better OS (hazard ratio [HR] 0.970; 95 % confidence interval [CI] 0.955-0.986); the effect did not change after we stratified patients into node-negative (HR 0.966; 95 % CI 0.933-1.000) and node-positive (HR 0.973; 95 % CI 0.955-0.991) groups.
Conclusion: The NLN count is an important independent prognostic factor for patients with thoracic ESCC treated with 3FLND.