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Stages of Colorectal Cancer

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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 tumor (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 tumor 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 tumor cannot be assessed. T0: There is no evidence of a tumor. Tis: The tumor is "in situ," meaning it was caught very early and has not grown beyond the lining of the colon or rectum. T1: The tumor 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: Tumor 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 labeled "Stage." Now go down to the row labeled "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	–

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Credits

By	Healthwise Staff
Primary Medical Reviewer	E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer	Kenneth Bark, MD - Surgery, Colon and Rectal
Last Revised	August 27, 2012

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Last Revised: August 27, 2012

Author: Healthwise Staff

Medical Review: E. Gregory Thompson, MD - Internal Medicine & Kenneth Bark, MD - Surgery, Colon and Rectal

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