Evaluation of preoperative staging for esophageal squamous cell carcinoma

Figure 2 Features used to stage esophageal squamous cell carcinoma according to the latest version of the TNM classification system[10]. *Tis = intraepithelial neoplasia. T1: cancer invades lamina propria, muscularis mucosa, or submucosa; T2: cancer invades muscularis propria; T3: cancer invades adventitia; T4a: resectable cancer invades adjacent structures, such as pleura, pericardium, or diaphragm; and T4b; unresectable cancer invades other adjacent structures, such as aorta, vertebral body, or trachea. N is classified as N0: no regional lymph node metastasis; N1: regional lymph node metastases involving 1 to 2 nodes; N2: regional lymph node metastases involving 3 to 6 nodes; and N3: regional lymph node metastases involving 7 or more nodes. M is classified as M0: no distant metastasis; and M1: distant metastasis. HGD: High-grade dysplasia.