Lymphatic invasion is a prognostic factor of pathological N0 esophageal squamous cell carcinoma

Adjuvant treatment after upfront esophagectomy for esophageal squamous cell carcinoma (ESCC) is indicated only for patients with lymph node metastasis in Japan. However, the recurrence rate after curative resection is high even for node-negative patients; thus, understanding the prognostic factors for patients with node-negative ESCC, which still remains unidentified, is important. Here, we aimed to reveal the prognostic factors for the long-term outcomes of patients with node-negative ESCC. Moreover, we compared the long-term outcomes among high-risk node-negative and node-positive patients. This single-institution retrospective study included 103 patients with pT1b-3N0 ESCC who underwent upfront surgery to identify the population at a high risk of recurrence. To compare overall survival (OS) and recurrence-free survival (RFS) between high-risk node-negative and node-positive patients, 51 node-positive ESCC patients with pStage IIIA or less who had undergone upfront surgery were also included. Univariable and multivariable analyses were performed using the Cox proportional hazard regression model. OS and RFS were compared using the log-rank test. Only lymphatic invasion (Ly+) was associated with worse 3-year OS (hazard ratio, 8.63; 95% confidence interval, 2.09-35.69; P = 0.0029) and RFS (hazard ratio, 4.87; 95% confidence interval, 1.69-14.02; P = 0.0034). The node-negative and Ly+ patients showed significantly worse OS (P = 0.0242) and RFS (P = 0.0114) than the node-positive patients who underwent chemotherapy. Ly+ is the only independent prognostic factor in patients with node-negative ESCC. Patients with node-negative and Ly+ ESCC may benefit from adjuvant treatment.