TNM system for intestinal cancer
Adenocarcinomas are typically staged using the American Joint Committee on Cancer's TNM system. Some types of cancers like carcinoid tumors do not have a standard staging system. In this case, the spread of the cancer is simply defined as localized, regional or distant. The intestinal cancer stages described here are for the more common adenocarcinomas and are defined using the TNM system.
The combined categories, T, N and M, create the stages 0 through IV:
- Tumor (T): The tumors are rated on a scale of 0 through 4, where T0 indicates no evidence of the primary tumor expanding into local tissue, and the increasing numbers (T1 through T4) describe the extent and spread of tumor into and through the intestinal wall. Carcinoma in situ tis describes an early cancer that has not gone beyond to the mucosa.
- Node (N): If cancer is found in the lymph nodes, the quantity of cancer cells found is rated using N1 or N2. Conditions where the cancer has not spread to the lymph nodes is indicated by N0.
- Metastasized (M): Cancer that has spread (metastasized) is indicated by M1. Otherwise, M0 is used if there are no signs of metastasis.
Each category (T, N and M) is assessed and rated. An X is used to denote insufficient information (the condition of the particular factor cannot be adequately assessed).