label: Stage I Esophageal Cancer AJCC v7
label_lc: stage i esophageal cancer ajcc v7
description: Stage I includes: For squamous cell carcinoma: IA (T1, N0, M0, G1, GX, Tumor location: Any); IB (T1, N0, M0, G2-3, Tumor location: Any); (T2-3, N0, M0, G1, GX, Tumor location: Lower, X).  For adenocarcinoma: IA (T1, N0, M0, G1-2, X); IB (T1, N0, M0, G3); (T2, N0, M0, G1-2, GX).  T1: Tumor invades lamina propria, muscularis mucosae, or submucosa.  T2: Tumor invades muscularis propria. T3: Tumor invades adventitia. N0: No regional lymph node metastasis.  M0: No distant metastasis.  G1: Well differentiated.  GX: Grade cannot be assessed-stage grouping as G1.  G2: Moderately differentiated.  G3: Poorly differentiated.  Tumor location: Location of the primary cancer site is defined by the position of the upper (proximal) edge of the tumor in the esophagus.  (AJCC 7th ed.)