When bowel cancer is diagnosed, it is given a number according to what stage it has reached. Doctors may also use a staging system known as TNM to provide more detail about the size and spread of the cancer.
The type of cancer you have, the stage it is at when you are diagnosed and your general level of health will determine what treatment you receive.
If you have early stage cancer you are likely to be offered surgery and possibly also chemotherapy and radiotherapy. If your cancer is diagnosed in the later stages, you might only have chemotherapy and radiotherapy as the spread may make surgery impossible.
How the numbered staging system works:
Stage 0 (also called carcinoma in situ or CIS)
This means you have early stage bowel cancer. You have some cancer cells in the lining of your bowel but they are contained with little or no risk of them having spread.
Stage 1 bowel cancer
If you have stage 1 bowel cancer, the cancer has grown through the inner lining of the bowel or into the muscle wall but has not reached the lymph nodes. Stage 1 is equivalent to TNM staging T1 or 2, N0, M0.
Stage 2 bowel cancer
Stage 2 bowel cancer means the cancer is localised but has not reached the lymph nodes.
- Stage 2A means the cancer has grown into your bowel’s outer covering. This is the same as T3, N0, M0.
- Stage 2B means the cancer has grown beyond the outer covering of your bowel into the adjacent organs or tissues. It has not spread to other parts of the body. This is the same as T4, N0, M0.
Stage 3 bowel cancer
There are three levels to stage 3 bowel cancer:
- Stage 3A bowel cancer may still be in the inner layer of the bowel wall or it may have grown into the muscle layer. It may have spread to between one and three lymph nodes nearby. This is the same as T1 or 2, N1, M0.
- Stage 3B means that the cancer has grown into the outer lining of the bowel wall, or into surrounding organs or tissues. Up to three lymph nodes may also contain cancer cells. This is the same as T3, N1, M0.
- Stage 3C means that the cancer can be any size. It has spread to four or more lymph nodes but not to other parts of the body. This is the same as any T, N2, M0.
Stage 4 bowel cancer
Stage 4 bowel cancer has spread to other parts of the body via the lymphatic system or bloodstream. It may be affecting the liver, lungs or bones. This is the same as any T, any N, M1.
TNM Staging (also called Duke’s staging)
T stands for tumour and describes how large the tumour has grown:
- T1 – only in the inner layer of the bowel
- T2 – into the muscle layer of the bowel
- T3 – into the outer lining of the bowel
- T4 – through the outer lining of the bowel and into other organs/parts of the bowel
N stands for nodes, or lymph nodes:
- N0 – no lymph nodes contain cancer cells
- N1 – up to 3 lymph nodes close to the bowel contain cancer cells
- N2 – there are 4 or more cancer cells in nearby lymph nodes
M stands for metastasis, which means the spread of cancer to other parts of the body:
- M0 – the cancer has not spread to other parts of the body
- M1 – the cancer has spread to other parts of the body
Mr Jamie Murphy is a Consultant Colorectal Surgeon who specialises in colorectal and gastrointestinal surgery and colonoscopy. His areas of expertise include:
Preventative bowel screening is also of high importance to us, and to you, to help prevent risk of disease in later life.
We place a high focus on prevention, as detecting the early signs or highlighting risk areas in advance, can greatly assist with the success of any treatment.