Bowel Cancer Stages
Bowel cancer takes around a decade to develop from a pre-cancerous polyp to Stage 4 cancer. After a bowel (colorectal) cancer diagnosis, doctors determine the stage of the disease before deciding how best to treat it. Most cancer types, including colorectal cancer, are grouped into stages ranging from 0 to 4.
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Bowel Cancer Stages
Stages are based on the cancer’s size, location and spread within the body. To establish the stage of colorectal cancer, your consultant is likely to consider all the information gathered during tests, examinations or biopsies leading up to a diagnosis.
Stage 1 – the cancer hasn’t spread outside the bowel wall.
Stage 2 – the cancer has grown into or through the outer layer of the bowel wall.
Stage 3 – the cancer has spread to nearby lymph nodes.
Stage 4 – the cancer has spread to other parts of the body.
Pre-cancerous cells (Stage 0)
Polyps (small growths on the inner lining of the gut) can develop as part of the ageing process. Polyps can sometimes become cancerous so, as a precaution, will often be removed in a routine colonoscopy. At this point, if cancer has started to develop, it will be no more than a few cells so often there will be no need for any follow-up treatment.
Stage 1 bowel cancer
At stage 1, colorectal cancer cells are found in deeper layers of the colon or rectum wall, but they haven’t spread beyond the wall. The following characteristics will be identified:
Cancer cells are found in the innermost layer lining the colon or rectum, and they have grown into the second layer of tissue (the submucosa).
The cancer may have also spread to a nearby muscle layer (muscularis propria) but hasn’t reached nearby lymph nodes.
Stage 2 bowel cancer
Stage 2 colorectal cancer cells have not yet spread to the lymph nodes but some may have spread through and beyond the wall of the colon or rectum, sometimes into nearby tissues or organs. The following characteristics will be identified:
Stage 2A: The cancer has spread through the layers of the colon or rectum wall and has reached the outermost layer, but no farther.
Stage 2B: The cancer has grown past the outermost layer of the colon or rectum wall but hasn’t spread to nearby tissues or organs.
Stage 2C: The cancer has spread past the outermost layer of the colon or rectum wall and has grown into nearby tissues or organs, but it hasn’t spread to lymph nodes or distant organs.
Stage 3 bowel cancer
In stage 3, colorectal cancer cells have spread to one or more nearby lymph nodes, but they have not grown beyond the lymph nodes and colon or rectum wall to other parts of the body. The following characteristics will be identified:
Stage 3A: The cancer has spread through the first two inner layers of the colon or rectum wall (mucosa and submucosa) and may have also reached the third layer (muscularis propria). It has also reached one to three nearby lymph nodes, or cancer cells are found near the lymph nodes.
Or the cancer has spread through the first two layers of the colon or rectum wall and has reached four to six nearby lymph nodes.
Stage 3B: The cancer has reached the outermost layer (serosa) of the colon or rectum wall. It may have spread through the tissue that lines the abdominal organs (visceral peritoneum) but has not yet reached nearby organs. Cancer is found in one to three nearby lymph nodes, or cancer cells are found near the lymph nodes.
Or the cancer has grown into the muscle layer or the outermost layer of the colon or rectum wall and has reached four to six nearby lymph nodes.
Or the cancer has grown through the first two layers of the colon or rectum wall and may have reached the muscle layer. Cancer is found in seven or more nearby lymph nodes.
Stage 3C: The cancer has grown past the colon or rectum wall and has spread to the tissue that lines the abdominal organs, but it has not spread to nearby organs. Cancer is found in four to six nearby lymph nodes.
Or the cancer has grown past the colon or rectum wall or has spread through the tissue that lines the abdominal organs. It’s found in seven or more nearby lymph nodes.
Or the cancer has spread past the wall of the colon or rectum and has grown into nearby organs or tissues. Cancer is found in at least one nearby lymph node, or cancer cells are found near the lymph nodes.
Stage 4 bowel cancer
At Stage 4, the cancer has spread beyond the colon or rectum to distant areas of the body, including tissues and/or organs. The following characteristics will be identified:
Stage 4A: The cancer has reached one area or organ that isn’t near the colon or rectum (such as the liver, lung, ovary or a faraway lymph node).
Stage 4B: The cancer has reached more than one area or organ that isn’t near the colon or rectum.
Stage 4C: The cancer has spread to distant parts of the tissue that lines the abdominal wall and may have reached other areas or organs.