NCIt definition : Stage IIB includes: T4a, N0, M0. T4a: Tumor invades through the visceral peritoneum,
including the acellular mucin or mucinous epithelium involving the serosa of the appendix
or serosa of the mesoappendix. N0: No regional lymph node metastasis. M0: No distant
metastasis. (AJCC 8th ed.);