Background: Currently, the number of negative lymph nodes (NLNs) has been paid increasing attention and is considered a prognostic indicator in diverse cancers. Therefore, it is necessary to explore the association between number of NLNs and prognosis in esophageal cancer (EC) patients.
Methods: Our data were obtained from the Surveillance, Epidemiology, and End Results 18 database. The X-tile plot was used to determine the optimal cut-off value of the number of NLNs, and propensity score matching (PSM) was performed according to the results of the X-tile plot.
Results: A total of 4777 patients were eligible, and 882 pairs of patients were included after PSM. The result of the X-tile plot revealed an optimal cut-off value of three NLNs. Multivariate Cox regression analysis revealed better EC-specific survival (ECSS) in patients with more than three NLNs (hazard ratio [HR] 0.68, 95% confidence interval [CI] 0.59-0.77; p < 0.001) compared with patients with three or fewer NLNs. A subgroup analysis revealed better ECSS in patients with more than three NLNs with one to two (HR 0.57, 95% CI 0.46-0.71; p < 0.001) or three to six (HR 0.68, 95% CI 0.50-0.92; p = 0.012) positive lymph nodes (PLNs).
Conclusions: More than three NLNs is associated with better survival in EC patients, especially when the number of PLNs is one to two or three to six. We confirm that the combination of the number of NLNs and number of PLNs can provide better prognostic guidance for EC.