Stages of Colon Cancer

Cancer stage describes the extent of cancer in the body, such as the size of the tumor, whether it has spread, and how far it has spread from where it first formed. It is important to know the stage of the colon cancer to plan the best treatment.  

There are several staging systems for cancer that describe the extent of the cancer. Colon cancer staging usually uses the TNM staging system. The cancer may be described by this staging system in your pathology report. Based on the TNM results, a stage (I, II, III, or IV, also written as 1, 2, 3, or 4) is assigned to your cancer. When talking to you about your diagnosis, your doctor may describe the cancer as one of these stages. 

Learn about tests to stage colon cancer. Learn more about Cancer Staging.

The following stages are used for colon cancer:

Stage 0 (Carcinoma in Situ)

In stage 0 colon cancer, abnormal cells are found in the mucosa (innermost layer) of the colon wall. These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 is also called carcinoma in situ.

Stage I (also called stage 1) colon cancer

In stage I colon cancer, cancer has formed in the mucosa (innermost layer) of the colon wall and has spread to the submucosa (layer of tissue next to the mucosa) or to the muscle layer of the colon wall.

Stage II (also called stage 2) colon cancer

Stage II colon cancer is divided into stages IIA, IIB, and IIC.

• Stage IIA: Cancer has spread through the muscle layer of the colon wall to the serosa (outermost layer) of the colon wall.
• Stage IIB: Cancer has spread through the serosa (outermost layer) of the colon wall to the tissue that lines the organs in the abdomen (visceral peritoneum).
• Stage IIC: Cancer has spread through the serosa (outermost layer) of the colon wall to nearby organs.

Stage III (also called stage 3) colon cancer

Stage III colon cancer is divided into stages IIIA, IIIB, and IIIC.

In stage IIIA, cancer has spread:

• through the mucosa (innermost layer) of the colon wall to the submucosa (layer of tissue next to the mucosa) or to the muscle layer of the colon wall. Cancer has spread to one to three nearby lymph nodes, or cancer cells have formed in tissue near the lymph nodes; or
• through the mucosa (innermost layer) of the colon wall to the submucosa (layer of tissue next to the mucosa). Cancer has spread to four to six nearby lymph nodes.

In stage IIIB, cancer has spread:

• through the muscle layer of the colon wall to the serosa (outermost layer) of the colon wall or has spread through the serosa to the tissue that lines the organs in the abdomen (visceral peritoneum). Cancer has spread to one to three nearby lymph nodes, or cancer cells have formed in tissue near the lymph nodes; or
• to the muscle layer or to the serosa (outermost layer) of the colon wall. Cancer has spread to four to six nearby lymph nodes; or
• through the mucosa (innermost layer) of the colon wall to the submucosa (layer of tissue next to the mucosa) or to the muscle layer of the colon wall. Cancer has spread to seven or more nearby lymph nodes.

In stage IIIC, cancer has spread:

• through the serosa (outermost layer) of the colon wall to the tissue that lines the organs in the abdomen (visceral peritoneum). Cancer has spread to four to six nearby lymph nodes; or
• through the muscle layer of the colon wall to the serosa (outermost layer) of the colon wall or has spread through the serosa to the tissue that lines the organs in the abdomen (visceral peritoneum). Cancer has spread to seven or more nearby lymph nodes; or
• through the serosa (outermost layer) of the colon wall to nearby organs. Cancer has spread to one or more nearby lymph nodes, or cancer cells have formed in tissue near the lymph nodes.

Stage IV (also called stage 4) colon cancer

Stage IV colon cancer is divided into stages IVA, IVB, and IVC.

• Stage IVA: Cancer has spread to one area or organ that is not near the colon, such as the liver, lung, ovary, or a distant lymph node.
• Stage IVB: Cancer has spread to more than one area or organ that is not near the colon, such as the liver, lung, ovary, or a distant lymph node.
• Stage IVC: Cancer has spread to the tissue that lines the wall of the abdomen and may have spread to other areas or organs.

Stage IV colon cancer is also called metastatic colon cancer. Metastatic cancer happens when cancer cells travel through the lymphatic system or blood and form tumors in other parts of the body. The metastatic tumor is the same type of cancer as the primary tumor. For example, if colon cancer spreads to the liver, the cancer cells in the liver are actually colon cancer cells. The disease is called metastatic colon cancer, not liver cancer. Learn more in Metastatic Cancer: When Cancer Spreads.

Colon cancer can recur (come back) after it has been treated.

Recurrent colon cancer is cancer that has come back after it has been treated. If colon cancer comes back, it may come back in the colon or in other parts of the body, such as the liver, lungs, or both. Tests will be done to help determine where the cancer has returned. The type of treatment for recurrent colon cancer will depend on where it has come back.

Learn more in Recurrent Cancer: When Cancer Comes Back. Information to help you cope and talk with your health care team can be found in the booklet When Cancer Returns.