They are typically staged using the American Joint Committee on Cancer's TNM (Tumor, node, metastasis) 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. Once the category is assigned, the cancer is diagnosed at one of the following stages:
Stage 0: The cancer has not grown beyond the mucosa.
Stage I (stage 1 intestinal cancer): In this stage, the disease has grown beyond the mucosa, but has not spread beyond the small intestine to other sites or lymph nodes.
Stage II (stage 2 intestinal cancer): The cancer has grown into or through the intestinal wall. At this stage, it may or may not have reached nearby organs. There is no evidence of spread of disease to lymph nodes or distant sites.
Stage III (stage 3 intestinal cancer): In stage III of intestinal cancer, the disease has metastasized to nearby lymph nodes. The tumor may be any size (T1 through T4). The cancer may or may not have reached nearby organs. Distant sites like the lung or liver remain unaffected.
Stage IV (stage 4 intestinal cancer): The cancer may be any size and has spread throughout the body to distant sites like the liver, lung or lining of the abdominal cavity.