The process used to find out if cancer has spread within the colon/rectum or to other parts of the body is called staging. Staging is important because it helps determine the best treatment plan.

Staging Defined

Stage 0: This is the earliest stage possible. Cancer hasn’t moved from where it started; it’s still restricted to the innermost lining of the colon. Stage 0 is also called Carcinoma in Situ.

Stage I: Cancer has begun to spread, but is still in the inner lining. Stage I is also called Dukes A colon cancer.

Stage II: Many of these cancers have grown through the wall of the colon and may extend into nearby tissue. They have not yet spread to the lymph nodes. Stage II is also called Dukes B colon cancer.

Stage III: Cancer has spread to lymph nodes, but has not been carried to distant parts of the body. Stage III is also called Dukes C colon cancer.

Stage IV: Cancer has been carried through the lymph system to distant parts of the body, most commonly lungs and liver. This is known as metastasis. Stage IV is also called Dukes D colon cancer.

Staging for Colon Cancer

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

Stage I: In stage I, cancer has formed and spread beyond the innermost tissue layer of the colon wall to the middle layers.

Stage II: In stage II, colon cancer is divided into stage IIA, stage IIB and stage 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 but has not spread to nearby organs.
  • Stage IIC: Cancer has spread through the serosa (outermost layer) of the colon wall to nearby organs.

The Oncotype DX® test for Stage II Colon Cancer Patients.

Stage III:  In stage III, colon cancer is divided into stage IIIA, stage IIIB, and stage IIIC.

  • Stage IIIA: Cancer has spread from the innermost tissue layer of the colon wall to the middle layers and has spread to as many as three lymph nodes.
  • Stage IIIB: Cancer has spread to as many as three nearby lymph nodes and has spread:
    • beyond the middle tissue layers of the colon wall; or
    • to nearby tissues around the colon or rectum; or
    • beyond the colon wall into nearby organs and/or through the peritoneum.
  • Stage IIIC: Cancer has spread to four or more nearby lymph nodes and has spread:
    • to or beyond the middle tissue layers of the colon wall; or
    • to nearby tissues around the colon or rectum; or
    • to nearby organs and/or through the peritoneum.

Stage IV:  In stage IV, cancer may have spread to nearby lymph nodes and has spread to other parts of the body, such as the liver or lungs.

Staging for Rectal Cancer

Stage 0: In stage 0, abnormal cells are found in the innermost lining of the rectum. These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 is also called carcinoma in situ.

Stage I: In stage I, cancer has formed and spread beyond the innermost lining of the rectum to the second and third layers and involves the inside wall of the rectum, but it has not spread to the outer wall of the rectum or outside the rectum.

Stage II: In stage II, cancer has spread outside the rectum to nearby tissue, but it has not gone into the lymph nodes (small, bean-shaped structures found throughout the body that filter substances in a fluid called lymph and help fight infection and disease).

Stage III: In stage III, cancer has spread to nearby lymph nodes, but it has not spread to other parts of the body.

Stage IV: In stage IV, cancer has spread to other parts of the body, such as the liver, lungs, or ovaries.

The Stages of Colorectal Cancer