The Prognostic Impact of Extracapsular Lymph Node Involvement in Esophageal Squamous Cell Carcinoma

Background The role of extracapsular lymph node involvement (ELNI) in esophageal cancer has not been fully investigated. We aim to assess its incidence and prognostic significance in patients with esophageal squamous cell carcinoma (ESCC) treated with and without neoadjuvant treatments. Methods Data of patients who underwent esophagectomy for ESCC in a single medical center was retrospectively reviewed. Patients with positive lymph node involvement were classified as either with ELNI or without ELNI (intracapsular lymph node involvement, ILNI). The impact of ELNI on overall survival (OS), disease-free survival (DFS), and disease recurrence was analyzed. Results A total of 336 patients, including 179 without (NCRT -) and 157 with (NCRT +) neoadjuvant chemoradiotherapy, were included. Seventy-two of 179 (40.2%) patients in NCRT - group were with positive lymph node, of whom 19 (26.4%) had ELNI, whereas 49 (31.2%) patients in NCRT + group had positive lymph node, of whom 25 (51.0%) had ELNI. In NCRT + group, patients with ELNI had worse outcome compared to those with ILNI in 5-year OS (10.4 vs. 13.8%, p = 0.008), and DFS (5.3 vs. 17.5%, p = 0.008). The presence of ELNI was also associated with more distant recurrence (p = 0.03). In contrast, there was no survival difference between patients with ELNI and ILNI in NCRT - group. Conclusions Compared with ILNI, ELNI is a significant poor prognostic factor in patients with ESCC treated with neoadjuvant treatments, but not in those with primary surgery.