The stage of a cancer describes its size and whether it has spread. Knowing the stage of the cancer helps doctors decide on the best treatment for you.
Cancer can spread in the body, either in the bloodstream or through the lymphatic system. The lymphatic system helps protect us from infection and disease. It is made up of fine tubes called lymphatic vessels that connect to groups of lymph nodes throughout the body. Your doctors will usually check the lymph nodes close to the small bowel to help find the stage of the cancer.
There are different staging systems for small bowel cancer. The staging system used by your doctor will depend on the type of small bowel cancer you have. The TNM staging system is the most commonly used system. It is used for adenocarcinoma of the small bowel.
T describes how far the tumour has grown into the wall of the small bowel, and whether it has grown into nearby tissues or organs.
N describes whether the cancer has spread to the lymph nodes.
M describes whether the cancer has spread to another part of the body (secondary or metastatic cancer).
T – Tumour
The small bowel wall is made up of layers of different tissues.
- T1 means the tumour is only in the inner layer of the small bowel, called the submucosa.
- T2 means the tumour has grown into the muscle layer of the small bowel wall but no further.
- T3 means the tumour has grown through the muscle layer into the layer before the outer lining of the small bowel wall (called the subserosa), but no further.
- T4 means the tumour has grown into the outer layer of the bowel wall (called the serosa). It may also be growing into the surrounding organs, such as the large bowel, bladder, stomach or pancreas.
N – Nodes
- N0 means no lymph nodes contain cancer cells.
- N1 means there are cancer cells in 1 to 3 nearby lymph nodes.
- N2 means there are cancer cells in 4 or more nearby lymph nodes.