Staging
However, an exact assessment of the tumor stage is often only possible after the operation, when the tumor has been removed and the surgical specimen (resected) and the lymph nodes have been examined histologically under a microscope. T-stages: T1: Infiltration of the mucous membrane (mucosa) or muscles T2: Infiltration of the connective tissue following the muscle layer (serosa) T3: Perforation of the last organ-enveloping layer (serosa, visceral peritoneum) and/or ingrowth (infiltration) into the liver or other neighbouring organs (e.g. duodenum, stomach, bile ducts). T4: Infiltration of the portal vein (vena portae) or hepatic artery (arteria hepatica) or infiltration of 2 or more neighboring organs N Stages: N0: No lymph node metastases detectable N1: Surrounding (regional) lymph node metastases between hepatic portal and duodenum (Ligamentum hepatoduodenale) affect N2: Other nearby lymph node metastases M stages: M0: No distant metastases detectable M1. Distant metastases (especially liver, later also lung)
- T1a: Mucosal infiltration
- T1b: Infiltration of the musculature
