Squamous cell carcinoma is the main subtype of esophageal cancer in East Asia. The effect of the number of lymph nodes (LNs) removed to treat middle and lower thoracic esophageal squamous cell carcinoma (ESCC) in China remains controversial. Therefore, the present study aimed to investigate the impact of the number of LNs removed during lymphadenectomy on the survival of patients with middle and lower thoracic ESCC. Data were obtained from the Sichuan Cancer Hospital and Institute Esophageal Cancer Case Management Database from January 2010 to April 2020. Either three-field systematic lymphadenectomy (3F group) or two-field systematic lymphadenectomy (2F group) was performed for ESCC cases with or without suspicious tumor-positive cervical LNs, respectively. Subgroups were designed for further analysis based on the quartile number of resected LNs. After 50.7 months of median follow-up, 1,659 patients who underwent esophagectomy were enrolled. The median overall survival (OS) of the 2F and 3F groups was 50.0 months and 58.5 months, respectively. The OS rates at 1, 3 and 5 years were 86, 57 and 47%, respectively, in the 2F group, and 83, 52 and 47%, respectively, in the 3F group (P=0.732). The average OS of the 3F B and D groups was 57.7 months and 30.2 months, respectively (P=0.006). In the 2F group, the OS between subgroups was not significantly different. In conclusion, resection of >15 LNs during two-field dissection in patients with ESCC undergoing esophagectomy did not affect their survival outcomes. In three-field lymphadenectomy, the extent of LNs removed could lead to different survival outcomes.

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Background: The incidence and mortality of esophageal cancer are high. Therefore, the authors aimed to investigate how the number of dissected lymph nodes (LNs) during esophagectomy for esophageal squamous cell carcinoma impacts overall survival (OS), particularly that of patients with positive LNs. Materials and methods: Data from 2010 to 2017 were obtained from the Sichuan Cancer Hospital and Institute Esophageal Cancer Case Management Database. Participants were divided into two groups: patients with negative lymph nodes (N0) and patients with positive lymph nodes (N+). The median number of resected LNs during surgery was 24; therefore, patients with 15–23 and those with 24 or more resected LNs were assigned to subgroups A and B, respectively. Results: After a median follow-up of 60.33 months, 1624 patients who underwent esophagectomy were evaluated; 60.53 and 39.47% had a pathological diagnosis of N+ or N0, respectively. The median OS was 33.9 months for the N+ group; however, the N0 group did not achieve the median OS. The mean OS was 84.9 months. In the N+ group, the median OS times of subgroups A and B were 31.2 and 37.1 months, respectively. The OS rates at 1, 3, and 5 years were 82, 43, and 34%, respectively, for subgroup A of the N+ group; they were 86, 51, and 38%, respectively, for subgroup B of the N+ group. Subgroups A and B of the N0 group exhibited no statistically significant differences. Conclusion: Increasing the number of LNs harvested during surgery to 24 or more could improve the OS of patients with positive LNs but not that of patients with negative LNs.