Depth of Invasion into the Circular and Longitudinal Muscle Layers in T2 Esophageal Squamous Cell Carcinoma Does Not Affect Prognosis or Lymph Node Metastasis: A Multicenter Retrospective Study

Background Although a greater depth of tumor invasion is correlated with a poorer prognosis in esophageal squamous cell carcinoma (ESCC), it remains controversial whether T2 ESCC should be subclassified by circular and longitudinal muscle invasion. We conducted a multicenter retrospective study to evaluate the relationship between the depth of invasion and long-term outcome and to identify the clinical significance of subclassifying T2 ESCC.