Colon cancer is generally classified into four main stages. In Stage 1, the cancer is limited to the inner layers of the bowel wall. In Stage 2, the cancer has spread through all layers of the bowel wall but has not reached nearby lymph nodes. Stage 3 refers to the situation where the cancer has spread to nearby lymph nodes. Stage 4 means the cancer has metastasized to distant organs such as the liver, lungs, or peritoneum.