Number of metastasis-positive lymph node stations is a simple and reliable prognostic factor following surgery in patients with esophageal cancer

The aim of this study was to evaluate the utility of lymph node metastasis classification based on the number of positive stations in patients undergoing surgical management of esophageal cancer. Of 257 patients who underwent curative esophagectomy, 126 patients with lymph node involvement underwent assessment of nodal metastasis mode according to the 7th edition of the TNM classification (UICC), and the Japanese Guidelines for the Clinical and Pathological Studies on Carcinoma of the Esophagus. Lymph node metastasis mode was divided into single station (S) and multi-station (M) groups. The S group was subclassified into single-node-single-station (SS) or multi-node-single-station (MS), and the M group was subclassified into multi-station in pN1 (2 metastasis positive nodes; MM-pN1) or multi-station in pN2 or 3 (MM-pN2,3) by TNM classification, multi-station-single-area (MMS) or multi-station-multi-areas (MMM). The correlation between prognosis and lymph node metastasis mode was assessed. A total of 47 patients were classified as S (MS, n=11; SS, n=36), and 79 patients were classified as M (MM-pN1, n=12; MM-pN2,3, n=67; MMM, n=55; MMS, n=24). Prognosis was poorer among the M- than in the S-classified patients (p=0.0035), whereas prognosis was not significantly different between the subgroups. In conclusion, lymph node metastasis classification based on the number of metastasis-positive stations is a useful predictor of prognosis in patients undergoing surgical management of esophageal cancer. This system relies on a simple classification method that combines the Japanese classification based on lymphatic spread and the TNM classification based on the number of positive lymph nodes.