If the biopsy shows that colon or rectal cancer is present, your doctor will need to know the disease’s extent (stage) to plan the best treatment. The stage is based on whether the tumor has invaded nearby tissues, whether the cancer has spread, and, if so, to what parts of the body.
According to the American Cancer Society, the TNM system, created by the American Joint Committee on Cancer (AJCC), is the most widely used.
TNM stands for:
Patients are given a T, N, and M status. When combined, they determine the stage of colorectal cancer.
There are five stages: stage 0 (zero) and stages I through IV (1 through 4). The stage provides a standard way of describing the cancer, so doctors can work together to plan the best treatment for your colorectal cancer.
T followed by a letter or number (0 to 4) is used to describe how deeply the primary tumor has grown into the bowel lining.
N followed by a letter or number (0 to 2) indicates whether the cancer has spread to lymph nodes near the colon and rectum (called regional lymph nodes).
M followed by a letter or number (0 to 1), describes cancer that has spread to other parts of the body, such as the liver or lungs. This is called distant metastasis.
The following chart from the American Cancer Society helps compare stages and TNM status.
|
AJCC Stage |
Stage grouping |
Stage description* |
|
0 |
Tis N0 M0 |
The cancer is in its earliest stage. This stage is also known as carcinoma in situ or intramucosal carcinoma (Tis). It has not grown beyond the inner layer (mucosa) of the colon or rectum. |
|
I |
T1 or T2 N0 M0 |
The cancer has grown through the muscularis mucosa into the submucosa (T1), and it may also have grown into the muscularis propria (T2). It has not spread to nearby lymph nodes (N0) or distant sites (M0). |
|
IIA |
T3 N0 M0 |
The cancer has grown into the colon or rectum’s outermost layers but has not gone through them (T3). It has not reached nearby organs. It has not spread to nearby lymph nodes (N0) or distant sites (M0). |
|
IIB |
T4a N0 M0 |
The cancer has grown through the colon or rectum wall but has not grown into other nearby tissues or organs (T4a). It has not yet spread to nearby lymph nodes (N0) or distant sites (M0). |
|
IIC |
T4b N0 M0 |
The cancer has grown through the colon or rectum wall and is attached to or has grown into other nearby tissues or organs (T4b). It has not yet spread to nearby lymph nodes (N0) or distant sites (M0). |
|
IIIA
|
T1 or T2 N1/N1c M0 |
The cancer has grown through the mucosa into the submucosa (T1), and it may also have grown into the muscularis propria (T2). It has spread to 1 to 3 nearby lymph nodes (N1) or into fat areas near the lymph nodes but not the nodes themselves (N1c). It has not spread to distant sites (M0). |
|
OR |
||
|
T1 N2a M0 |
The cancer has grown through the mucosa into the submucosa (T1). It has spread to 4 to 6 nearby lymph nodes (N2a). It has not spread to distant sites (M0). |
|
|
IIIB
|
T3 or T4a, N1/N1c M0 |
The cancer has grown into the outermost layers of the colon or rectum (T3) or through the visceral peritoneum (T4a) but has not reached nearby organs. It has spread to 1 to 3 nearby lymph nodes (N1a or N1b) or into areas of fat near the lymph nodes but not the nodes themselves (N1c). It has not spread to distant sites (M0). |
|
OR |
||
|
T2 or T3 N2a M0 |
The cancer has grown into the muscularis propria (T2) or the outermost layers of the colon or rectum (T3). It has spread to 4 to 6 nearby lymph nodes (N2a). It has not spread to distant sites (M0). |
|
|
OR |
||
|
T1 or T2 N2b M0 |
The cancer has grown through the mucosa into the submucosa (T1), and it may also have grown into the muscularis propria (T2). It has spread to 7 or more nearby lymph nodes (N2b). It has not spread to distant sites (M0). |
|
|
IIIC
|
T4a N2a M0 |
The cancer has grown through the wall of the colon or rectum (including the visceral peritoneum). Still, it has not reached nearby organs (T4a). It has spread to 4 to 6 nearby lymph nodes (N2a). It has not spread to distant sites (M0). |
|
OR |
||
|
T3 or T4a N2b M0 |
The cancer has grown into the outermost layers of the colon or rectum (T3) or through the visceral peritoneum (T4a) but has not reached nearby organs. It has spread to 7 or more nearby lymph nodes (N2b). It has not spread to distant sites (M0). |
|
|
OR |
||
|
T4b N1 or N2 M0 |
The cancer has grown through the colon or rectum wall and is attached to or has grown into other nearby tissues or organs (T4b). It has spread to at least one nearby lymph node or into areas of fat near the lymph nodes (N1 or N2). It has not spread to distant sites (M0). |
|
|
IVA |
Any T Any N M1a |
The cancer may or may not have grown through the wall of the colon or rectum (Any T). It might or might not have spread to nearby lymph nodes. (Any N). It has spread to 1 distant organ (such as the liver or lung) or distant set of lymph nodes, but not to distant parts of the peritoneum (the lining of the abdominal cavity) (M1a). |
|
IVB |
Any T Any N M1b |
The cancer might or might not have grown through the wall of the colon or rectum (Any T). It might or might not have spread to nearby lymph nodes (Any N). It has spread to more than one distant organ (such as the liver or lung) or distant set of lymph nodes, but not to distant parts of the peritoneum (the lining of the abdominal cavity) (M1b). |
|
IVC |
Any T Any N M1c |
The cancer might or might not have grown through the wall of the colon or rectum (Any T). It might or might not have spread to nearby lymph nodes (Any N). It has spread to distant parts of the peritoneum (the lining of the abdominal cavity) and may or may not have spread to distant organs or lymph nodes (M1c). |
*The following additional categories are not listed in the table above:
NX: Regional lymph nodes cannot be assessed due to a lack of information.