[The current TNM system for gastrointestinal tumors part I]

The present review describes the changes in the new 7th edition of the TNM system for tumors of the upper gastrointestinal tract. The description of esophageal tumor localization has been simplified and this new classification now includes tumors of the esophagogastric junction as well as the proximal 5 cm of the stomach. The regional lymph nodes of the esophagus now include celiac lymph nodes, a change which is important for therapeutic decision making. The categories T1 and T4 have been further subclassified. The N categorization now considers not only the presence of metastases but also the number of lymph node metastases within three categories. The T and N categories of stomach tumours (as well as the stage groups) have been modified to ensure a significantly better correlation to the prognosis. The number of lymph nodes has been adapted to 16 to classify pN0. Only slight modifications have been introduced in tumors of the small bowel.