Risk Factors and Prognostic Impact of Mediastinal Lymph Node Metastases in Patients with Esophagogastric Junction Cancer.

Purpose: We retrospectively investigated the risk factors for mediastinal lymph node (MLN) metastasis in esophagogastric junction (EGJ) cancer with an epicenter within 2 cm above and below the anatomical cardia, including both adenocarcinoma (AC) and squamous cell carcinoma (SCC).
Methods: Fifty patients who underwent initial surgery for EGJ cancer from January 2002 to December 2013 were included in this study. We defined metastatic lymph nodes as pathological metastases in resected specimens and recurrence within 2 years postoperatively.
Results: Thirty-four patients had AC and 16 had SCC; 24 patients underwent transhiatal resection and 26 underwent transthoracic resection. MLN metastasis was observed in 13 patients (26%) regardless of the histological type, 9 of whom had metastasis in the upper and middle mediastinum. Metastasis occurred when the esophageal invasion length (EIL) exceeded 20 mm. In addition, 10/13 patients had stage pN2-3 cancer. Multivariable analysis identified EIL ≥ 20 mm and stage pN2-3 as significant risk factors for MLN metastasis. The 5-year overall survival was 38% and 65% in the MLN-positive and -negative groups, respectively (p = 0.12). Multivariable Cox regression analysis showed that only stage pN2-3, and not the presence of MLN metastasis, was a significantly poor prognostic factor.
Conclusion: MLN metastasis in EGJ cancer may have a close association with the EIL of the tumor, but the presence of MLN metastasis itself was not a poor prognostic factor. The significance and indications for MLN dissection should be clarified in prospective clinical trials.