Table 1.1: Staging classification of upper third EC (AJCC 7) T (primary tumor) Stage TNM Grade Tis High-grade dysplasia 0 TisN0M0 1, X T1a Tumor invades lamina propria or muscularis mucosae IA T1N0M0 1, X T1b Tumor invades submucosa IB T1N0M0 2, 3 T2 Tumor invades muscularis propria IIA T2 - 3N0M0 1, X T3 Tumor invades adventitia IIB T2 - 3N0M0 T1 - 2N1M0 2, 3 Any T4a invades pleura, pericardium, or diaphragm T4b Invades the aorta, vertebral body, trachea, etc. IIIA T1 - 2N2M0 T3N1M0 T4aN0M0 Any Any Any N (lymph node) N0 No regional lymph node metastasis N1 Metastasis in 1 - 2 regional lymph nodes IIIB T3N2M0 Any N2 Metastasis in 3 - 6 regional lymph nodes IIIC T4aN1 - 2M0 T4bNanyM0 TanyN3M0 Any Any Any N3 Metastasis in seven or more regional lymph nodes M (distant metastasis) M0 No distant metastasis M1 Distant metastasis IV M1 Any 1.1.3 Treatment Currently, dCRT is recommended as a first-line treatment for the advanced stage of upper third EC (T1b-T4N0-3M0).