Stages of Colorectal Cancer
Topic Overview
The type of treatment you will receive for your
colorectal cancer depends on what stage it is in.
Staging is a process doctors use to describe how far the cancer has
spread.
Although there are several methods of staging, most doctors now use
the TNM method. The TNM method is based on the size of the tumour (T), the
spread of the cancer into nearby lymph nodes (N), and the spread of the cancer
to other body parts (M, for metastasis). Some doctors still use an older method
of staging called Dukes.
TNM staging labels | T (describes tumour size and how deeply
it has penetrated the tissue layers of the colon or rectum) | N (describes how far the cancer has
spread to nearby lymph nodes) | M (describes whether the cancer has
spread to other parts of the body—metastasized) |
|---|
- TX: The tumour cannot be assessed.
- T0: There is no evidence of a tumour.
- Tis: The tumour is
"in situ," meaning it was caught very early and has not grown beyond the lining
of the colon or rectum.
- T1: The tumour has
grown through the lining and into the connective tissue.
- T2: The cancer has grown into the thick inner
muscle.
- T3: The cancer has grown completely
through the thick inner muscle. It has spread to the outer lining but not to
any nearby organs or tissues.
- T4a: The cancer
has spread completely through the wall of the colon or rectum and to the surface of nearby
organs.
- T4b: The cancer has spread completely through the wall of the colon or rectum and into nearby tissues or organs.
| - N0: Cancer has not
spread to lymph nodes.
- N1: Cancer cells are
found in 1 to 3 regional lymph nodes.
- N1a: Cancer cells are found in 1 regional lymph node.
- N1b: Cancer cells are found in 2–3 regional lymph nodes.
- N1c: Tumour deposits in the nearby tissues without the cells spreading to the regional nodes.
- N2:
Cancer cells are found in 4 or more regional lymph nodes.
- N2a: Cancer cells are found in 4–6 regional lymph nodes.
- N2b: Cancer cells are found in 7 or more regional lymph nodes.
| - M0: Cancer cells
have not spread to other parts of the body.
- M1: Cancer cells have spread to other parts of the
body.
- M1a: Cancer cells have spread to one organ or site, such as the liver, lung, ovary, or non-regional node.
- M1b: Cancer cells have spread to more than one organ or site in the peritoneum.
|
Let’s say your doctor has told you your cancer is at stage II. In the
table below, find the column labelled "Stage." Now go down to the row
labelled "II." In the columns to the right are the TNM staging system. You can find a description of each TNM label in the table above.
The Dukes staging system is shown in the far right column. This lists the stages as A, B, C, and D. The
Dukes stages A through D are the same as TNM stages I through IIIC.
How colorectal cancer is staged
| Stage | T | N | M | Dukes |
|---|
0 | Tis | N0 | M0 | – |
I | T1 T2 | N0 N0 | M0 M0 | A A |
IIA | T3 | N0 | M0 | B |
IIB | T4a | N0 | M0 | B |
IIC | T4b | N0 | M0 | B |
IIIA | T1–T2 T1 | N1/N1c N2a | M0 M0 | C C |
IIIB | T3–T4a T2–T3 T1–T2 | N1/N1c N2a N2b | M0 M0 M0 | C C C |
IIIC | T4a T3–T4a T4b | N2a N2b N1–N2 | M0 M0 M0 | C C C |
IVA | Any T | Any N | M1a | – |
IVB | Any T | Any N | M1b | – |
Credits
| By | Healthwise Staff |
|---|
| Primary Medical Reviewer | Kathleen Romito, MD - Family Medicine |
|---|
| Primary Medical Reviewer | Andrew Swan, MD, CCFP, FCFP - Family Medicine |
|---|
| Specialist Medical Reviewer | Arvydas D. Vanagunas, MD - Gastroenterology |
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| Last Revised | December 30, 2010 |
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Last Revised:
December 30, 2010
