Colorectal cancer

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Stages of colorectal cancer

Staging describes or classifies a cancer based on how much cancer there is in the body and where it is when first diagnosed. This is often called the extent of cancer. Information from tests is used to find out the size of the tumour, which parts of the colon or rectum have cancer, whether the cancer has spread from where it first started and where the cancer has spread. Your healthcare team uses the stage to plan treatment and estimate the outcome (your prognosis).

The most common staging system for colorectal cancer is the TNM system. For colorectal cancer there are 5 stages – stage 0 followed by stages 1 to 4. Often the stages 1 to 4 are written as the Roman numerals I, II, III and IV. Generally, the higher the stage number, the more the cancer has spread. Talk to your doctor if you have questions about staging.

When describing the stage, doctors may use the words local, regional or 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.

Find out more about staging cancer.

The colon and rectum are made up of different layers of tissues. The stage often depends on which layer the tumour has grown into.

Diagram of the layers of the colon and rectum

Stage 0 (carcinoma in situ)

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

Stage 1

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

Stage 2

Stage 2 can be divided into stages 2A, 2B and 2C.

For stage 2A, the tumour has grown into the layer of tissue between the muscularis propria and serosa, or it has grown into tissues beyond the muscularis propria (when there is no serosa).

For stage 2B, the tumour has grown through the membrane that covers and supports the colon and rectum (called the serosa or visceral peritoneum).

For stage 2C, the tumour has grown through the wall of the colon or rectum and into other organs or areas, such as the bladder, prostate or uterus.

Stage 3

There are cancer cells in lymph nodes near the colon or rectum. Stage 3 can be divided into stages 3A, 3B and 3C depending on where the tumour has grown and how many lymph nodes have cancer.

Stage 4

The cancer has spread to other parts of the body (called distant metastasis), such as to the liver or lungs. This is also called metastatic colorectal cancer. The cancer may be in only 1 organ or in distant lymph nodes (stage 4A). It may be in more than 1 organ (stage 4B). The cancer may be in the peritoneum (stage 4C).

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 where it first started, it’s called regional recurrence. It can also recur in another part of the body. This is called distant metastasis or distant recurrence.

epithelium

A tissue made up of epithelial cells. It makes up the surface of the skin. It also lines hollow areas of the body (called cavities), glands and the passages of the respiratory, digestive, reproductive and urinary systems.

peritoneum

The membrane that lines the walls of the abdomen and pelvis (parietal peritoneum), and covers and supports most of the abdominal organs (visceral peritoneum).

Stories

Brock Taraba Brock has been cancer free for over a decade, thanks to the support we received from the Canadian Cancer Society.

Read Brock's story

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