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Colorectal cancer

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Staging colorectal cancer

Staging is a way of describing or classifying a cancer based on the extent of cancer in the body. Extent includes the amount of cancer and where the cancer is in the body. Your healthcare team uses the stage to plan treatment and estimate your prognosis.

The most common staging system for colorectal cancer is the TNM system. Each stage is given a number from 0 to 4. Stages 1 to 4 are usually given as the Roman numerals I, II, III and IV. Generally, the higher the number, the more the cancer has spread.

When describing the stage, doctors may use the terms local, regional and distant. Local means that the cancer is only in the colon or rectum and has not spread to other parts of the body. Regional means close to or around the colon or rectum. Distant means in a part of the body farther from the colon or rectum.

TNM descriptions

T describes how far the primary tumour has grown into and around the colon or rectum. T is usually given as a number from 1 to 4. A higher number means that the tumour has grown farther into the colon or rectum and nearby tissues.

 

N describes the lymph nodes near the colon or rectum. N0 means the cancer hasn’t spread to the lymph nodes. N1, N2 or N3 means cancer has spread to lymph nodes and describes the number of lymph nodes that contain cancer.

 

M describes whether or not the cancer has spread, or metastasized, to other parts of the body. M0 means that cancer has not spread to other parts of the body. M1 means that it has spread to other parts of the body.

Stage 0 (or carcinoma in situ)

TNMDescription

Tis

N0

M0

Cancer cells are only in the inner lining of the colon or rectum (called the mucosa). They may be in the epithelium, or they may have grown into the layer of connective tissue in the mucosa (called the lamina propria). Cancer cells have not grown past the inner muscle layer of the mucosa (called the muscularis mucosa).

Stage I

TNMDescription

T1 or T2

N0

M0

The tumour has grown into the layer of connective tissue that surrounds the mucosa (called the submucosa) or into the thick outer muscle layer of the colon or rectum (called the muscularis propria).

Stage II

StageTNMDescription

IIA

T3

N0

M0

The tumour has grown into the subserosa layer (one of the outer layers between the muscularis propria and serosa) of the colon or rectum, or it has grown into soft tissues surrounding the colon and rectum (called pericolorectal tissues).

IIB

T4a

N0

M0

The tumour has grown through the membrane that covers and supports the colon and rectum (called the visceral peritoneum).

IIC

T4b

N0

M0

The tumour has grown through the wall of the colon or rectum and into other organs or structures.

Stage IIIA

TNMDescription

T1 or T2

N1

M0

The tumour has grown into the layer of connective tissue that surrounds the mucosa (called the submucosa) or into the thick outer muscle layer of the colon or rectum (called the muscularis propria).

There is regional lymph node metastasis. There are cancer cells in 1–3 lymph nodes near the colon or rectum.

T1

N2a

M0

The tumour has grown into the layer of connective tissue that surrounds the mucosa (called the submucosa).

There is regional lymph node metastasis. There are cancer cells in 4–6 lymph nodes near the colon or rectum.

Stage IIIB

TNMDescription

T3 or T4a

N1

M0

One of the following applies:

  • The tumour has grown into the subserosa layer (one of the outer layers between the muscularis propria and serosa) of the colon or rectum.
  • The tumour has grown into soft tissues surrounding the colon and rectum (called pericolorectal tissues).
  • The tumour has grown through the membrane that covers and supports the colon and rectum (called the visceral peritoneum).

There is regional lymph node metastasis. There are cancer cells in 1–3 lymph nodes near the colon or rectum.

T2 or T3

N2a

M0

One of the following applies:

  • The tumour has grown into the thick outer muscle layer of the colon or rectum (called the muscularis propria).
  • The tumour has grown into the subserosa layer (one of the outer layers) of the colon or rectum.
  • The tumour has grown into soft tissues surrounding the colon and rectum (called pericolorectal tissues).

There is regional lymph node metastasis. There are cancer cells in 4–6 lymph nodes near the colon or rectum.

T1 or T2

N2b

M0

The tumour has grown into the layer of connective tissue that surrounds the mucosa (called the submucosa) or into the thick outer muscle layer of the colon or rectum (called the muscularis propria).

There is regional lymph node metastasis. There are cancer cells in 7 or more lymph nodes near the colon or rectum.

Stage IIIC

TNMDescription

T4a

N2a

M0

The tumour has grown through the membrane that covers and supports the colon and rectum (called the visceral peritoneum).

There is regional lymph node metastasis. There are cancer cells in 4–6 lymph nodes near the colon or rectum.

T3 or T4a

N2b

M0

One of the following applies:

  • The tumour has grown into the subserosa layer (one of the outer layers) of the colon or rectum.
  • The tumour has grown into soft tissues surrounding the colon and rectum (called pericolorectal tissues).
  • The tumour has grown through the membrane that covers and supports the colon and rectum (called the visceral peritoneum).

There is regional lymph node metastasis. There are cancer cells in 7 or more lymph nodes near the colon or rectum.

T4b

N1 or N2

M0

The tumour has grown through the wall of the colon or rectum and into other organs or structures.

There is regional lymph node metastasis (there are cancer cells in lymph nodes near the colon or rectum).

Stage IV

StageTNMDescription

IVA

any T

any N

M1a

The tumour has grown into any layer of the colon or rectum.

There may be regional lymph node metastasis (cancer cells may be in lymph nodes near the colon and rectum).

There is distant metastasis (cancer has spread to other parts of the body). Cancer is in only 1 organ, such as the liver or lungs, or it is in distant lymph nodes.

IVB

any T

any N

M1b

The tumour has grown into any layer of the colon or rectum.

There may be regional lymph node metastasis (cancer cells may be in lymph nodes near the colon and rectum).

There is distant metastasis (cancer has spread to other parts of the body). Cancer is in more than 1 organ, or it is in the peritoneum (the membrane that lines the walls of the abdomen and pelvis, and covers and supports most of the organs in the abdomen).

Recurrent colorectal cancer

Recurrent colorectal cancer means that the cancer has come back after it has been treated. If it comes back in the same place that the cancer first started, it’s called local recurrence. If it comes back in tissues or lymph nodes close to the primary tumour, it’s called regional recurrence. It can also recur in another part of the body, which is called a distant metastasis.

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