Colorectal Cancer Staging

As colorectal cancer grows, it can spread through the wall of the colon or rectum. Then, like all cancers, it can spread (metastasize) to other parts of the body. The stage of your cancer is a way doctors describe how deep and how far your cancer has spread. Knowing the stage is important. The stage is a primary factor in deciding what treatment to use.

Stage groupings

Stage groupings are determined by combining the T, N, and M values from the TNM system. These groupings give an overall description of how advanced your cancer is. A stage grouping can have a value of 0 or a value assigned by a Roman numeral I through IV (1 through 4). The higher the value, the more advanced your cancer is.

These are the stage groupings of colorectal cancer and what they mean.

Stage 0 colorectal cancer

In this stage, cancer is only in the innermost lining of your colon. It has not spread and is in its earliest stage. This stage is also called carcinoma in situ.

Stage 1 colorectal cancer

In this stage, the cancer has spread to the middle layers of the lining of your colon. It has not spread to the lymph nodes or distant sites. This stage is sometimes called Dukes' A colon cancer.

Stage 2 colorectal cancer

This stage is sometimes called Dukes' B colon cancer. It is divided into three groups:

  • Stage IIA: In this stage, the cancer has grown into the outermost layers of the colon or rectum but has not gone through them. It still has not spread to the lymph nodes or to distant sites.
  • Stage IIB: The cancer has grown through the wall of the colon or rectum but has not grown into nearby organs. It has not spread to nearby lymph nodes or distant sites.
  • Stage IIC: The cancer has spread outside your colon to nearby tissues or organs. It has still not spread to the lymph nodes or to distant sites.
Stage 3 colorectal cancer

Stage 3 (III) colorectal cancer is sometimes called Dukes' C colon cancer. It is divided into three sub-stages: stage IIIA, stage IIIB, and stage IIIC.

Stage IIIA: The cancer has spread to the middle layers of your colon wall and has also spread to one to three lymph nodes. It hasn't spread to distant sites, though.

Stage IIIB: One of the following applies:

  • The cancer has grown into or through the outer layers of the colon or rectum but hasn't spread to nearby organs. It has spread to one to three nearby lymph nodes. It has not spread to distant sites.
  • The cancer has grown into the middle layers or outer of the colon or rectum and has spread to four to six nearby lymph nodes. It hasn't spread to distant sites.
  • The cancer has grown into the first or middle layers of the colon or rectum, and has spread to seven or more nearby lymph nodes. It hasn't spread to distant sites.

Stage IIIC: One of the following applies:

  • The cancer has grown through the outer layers of the colon or rectum but hasn't reached nearby organs. It has spread to four to six nearby lymph nodes, but not to distant sites.
  • The cancer has grown into or through the outer layers of the colon or rectum but hasn't reached nearby organs. It has spread to seven or more nearby lymph nodes, but not to distant sites.
  • The cancer has grown into or through the outer layers of the colon or rectum and has reached nearby organs. It has spread to one or more nearby lymph nodes, but not to distant sites.
Stage 4 colorectal cancer

This stage is sometimes called Dukes' D colon cancer. This stageis divided into two sub-stages:

  • Stage IVA: The cancer may or may not have grown through the wall of the colon or rectum, and it may or may not have reached nearby lymph nodes. It has spread to one distant organ (such as the lungs or liver) or one distant set of lymph nodes.
  • Stage IVB: The cancer may or may not have grown through the wall of the colon or rectum, and it may or may not have reached nearby lymph nodes. It has spread to more than one distant organ (such as the liver or the lungs) or set of distant lymph nodes, or it has spread to distant parts of the peritoneum (the lining of the abdominal cavity).

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