Impact of lymph node yield on survival of patients with metastatic esophageal cancer: a population-based retrospective study

Esophageal cancer is the seventh most common cancer worldwide, and its related mortality remains high. The association between lymph node yield and survival outcomes in patients with distant lymph node metastatic esophageal cancer has not been well studied. This study aimed to investigate the impact of LNY on the survival of patients with metastatic esophageal cancer and to identify prognostic factors affecting survival.

A total of 825 patients with metastatic esophageal cancer who underwent primary tumor resection were identified from the Surveillance, Epidemiology, and End Results database between 2000 and 2021. Survival curves were plotted using the Kaplan-Meier method and compared with the log-rank test. Propensity score matching was used to balance differences between groups. Univariate and multivariate Cox proportional hazards regression models were used to analyze prognostic factors.

Among the 825 patients included in this study, at least 6 LNYs were found to be beneficial for survival outcomes in the majority of mEC patients. Before propensity matching, the OS and CSS of the LNY > 6 group were significantly better than those of the LNY ≤ 6 group (median OS was 22.32 months and 13.3 months, respectively, P < 0.05). After propensity matching, the survival outcomes of the LNY > 6 group were still better than those of the LNY ≤ 6 group. Multivariate Cox regression analysis showed that age, race, pathological grade, and specific histological types were independent risk factors for OS. Subgroup analysis showed that patients with LNY > 6 benefited in most subgroups.

This study shows that the number of LNY is significantly associated with survival in patients with distant metastatic esophageal cancer, and adequate lymph node dissection may have association with improved survival. This finding provides an important basis for clinical decision-making and the design of future clinical trials.