Stage II includes: (T2a, N0, M0); (T2b, N0, M0). T2a: Tumor invades superficial muscularis propria (inner half). T2b: Tumor invades deep muscularis propria (outer half). N0: No regional lymph node metastasis. M0: No distant metastasis. (AJCC 8th ed.) [from
NCI]