Stage I includes: T0-2, N0, M0. T0: No evidence of primary tumor. T1: Tumor invades the lamina propria, muscularis mucosae, or submucosa. T2: Tumor invades the muscularis propria. N0: No regional lymph node metastasis. M0: No distant metastasis. (AJCC 8th ed.) [from
NCI]