Staging
Staging is an important part of diagnosis, treatment planning, and predictions of long term survival. Once a stage is decided at initial diagnosis it does not change, although the cancer may recur or spread later.
As colorectal cancer progresses from Stage 0 to Stage IV, the cancer cells grow outward through the layers of the colon or rectum wall and spread to nearby lymph nodes and to other organs.
Colon and rectal cancer staging depends on three factors:
- T—for Tumor: How far the tumor extends from the inner lining of the colon through the layers of its walls. See diagram below.
- N—for Nodes: Whether cancer cells are found in the lymph nodes draining the colon near the site of the cancer and how many nodes are affected. Lymph nodes are small, bean-shaped structures found throughout the body that filter substances in a fluid called lymph and help fight infection and disease).
- M—for Metastasis: Whether cancer has spread beyond the colon and its adjacent tissues to distant organs like the lungs or liver.
Colon and rectal cancer have similar definitions of staging.
Stage 0 (Carcinoma in Situ)
Colorectal: (Ts,N0,M0) In stage 0, the cancer is found in the innermost lining (mucosa) of the colon or rectum only. Stage 0 cancer is also called carcinoma in situ.
Stage I
Colon (T1,N0, M0 or T2,N0, M0) In stage I, the cancer has spread beyond the innermost tissue layer of the colon wall to the middle layers.
Rectal: In stage I, cancer has 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
Colon: Stage II colon cancer is divided into stage IIA and stage IIB.
- Stage IIA (T3,N0,M0): Cancer has spread beyond the middle tissue layers of the colon wall or has spread to nearby tissues around the colon.
- Stage IIB: (T4,N0,M0): Cancer has spread beyond the colon wall into nearby organs and/or through the serosa (tissue lining the colon).
Rectal: In stage II, cancer has spread outside the rectum to nearby tissue, but it has not gone into the lymph nodes.
Stage III
Colon
- Stage IIIA (T1,N1,M0) or (T2,N1,M0): Cancer has spread from the innermost layer of the colon wall to the middle layers and has spread to as many as 3 lymph nodes.
- Stage IIIB (T3,N1,MO or T4,N1,M0): Cancer has spread to as many as 3 nearby lymph nodes (N1) 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 serosa.
- Stage IIIC (Any T,N2,M0): Cancer has spread to 4 or more nearby lymph nodes (N2) 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 serosa.
Rectal: In stage III, cancer has spread to nearby lymph nodes, but it has not spread to other parts of the body.
Stage IV
Colorectal (Any T Any N, M1)
In stage IV, cancer has spread to other parts of the body, such as the liver, lungs, abdominal lining (peritoneum), or ovaries.
Recurrent
Recurrent cancer is cancer that has returned after treatment. It may be:
- Locally recurrent: returns in the region of the colon or rectum
- Distantly recurrent or metastatic: Returns somewhere in the body beyond the original location in the colon or rectum
Where Can You Go for More Information?
American Cancer Society How is Colorectal Cancer Staged has detailed information about colon and rectal cancer staging.
American Joint Committee on Cancer (AJCC) has more general information about cancer staging in What is Cancer Staging.
Cancer.Net, patient information from the American Society of Clinical Oncology, has staging information that includes good graphics and information about cancer grades.
Last Update: June 25, 2008
Medical Review
This page is under review by C3's medical review network.
