There are five major stages of colon cancer: 0, I, II, III and IV. Stages II through IV are also divided into substages that indicate how the cancer has spread within each stage, according to the National Cancer Institute.
In Stage 0, abnormal cells are found on the inner lining (mucosa) of the colon and may become cancerous, as explained by the National Cancer Institute. In Stage I, abnormal cells have developed into cancer and have spread from the mucosa to the submucosa, and they have also possibly spread to the colon's muscle layer.
In Stage II, cancer has spread through the muscle layer to the tissues surrounding the colon, but it has not yet spread to the lymph nodes, as About Health explains. Stages IIA through IIC describe when the cancer has spread through the muscle layer (IIA) to the outermost layer of the colon wall (IIB) or through the outermost wall to surrounding tissues.
In Stage III, cancer has spread to the lymph nodes surrounding the colon and to at least the inner and middle layers of the colon wall, according to the National Cancer Institute. Stage IIIA describes cancer that has moved to one to six lymph nodes. Stage IIIB describes cancer that has spread through all layers of the colon wall and into up to three lymph nodes, or it refers to when cancer is contained in the inner and middle layers but has spread to at least seven lymph nodes. In Stage IIIC, cancer is found in all layers of the colon wall and four or more lymph nodes, or it has spread to nearby organs. Stage IVA describes cancer that has spread to one organ not near the colon, and IVB describes cancer that has spread to two or more organs not near the colon.