The stage of a cancer is a term used to describe its size and whether it has spread beyond its original site. Knowing the extent of the cancer helps the doctors to decide on the most appropriate treatment.
A commonly used staging system for cancer of the oesophagus is described below:
Stage 0 or carcinoma in situ (CIS) – This is a very early stage of oesophageal cancer. There are cancer cells in the lining of the oesophagus, but they are contained entirely within the lining. Oesophageal cancer is not often diagnosed this early, as there are usually no symptoms at this stage.
Stage 1 – The cancer is found only in the surface layers of the lining of the oesophagus or in a small part of the oesophagus. It has not spread to nearby tissues, lymph nodes or other organs.
Stage 2 – This means that the cancer has either grown into the muscle layer of the oesophageal wall or spread to nearby lymph nodes, but has not spread to any other organs. If the cancer has not spread to nearby lymph nodes, it is stage 2A. If the cancer has spread to nearby lymph nodes, it is stage 2B.
Stage 3 – The cancer has grown through the wall of the oesophagus. It may also have spread to nearby lymph nodes and other body tissues close to the oesophagus, but there is no spread to other parts of the body.
Stage 4 – The cancer has spread to lymph nodes and other parts of the body, such as the liver, lungs or stomach and is known as secondary or metastatic cancer.
Your doctors may also describe your cancer using the TNM staging system.
T describes the size of the tumour. There are five different stages ranging from T0–T4.
N describes whether the cancer has spread to the lymph nodes. There are four stages depending upon the number of lymph nodes that are involved, ranging from N0–N3.
M describes whether the cancer has spread to another part of the body, such as the liver or the lungs (secondary or metastatic cancer). There are two stages: M0 is where there are no metastases; M1 is where there are metastases.
The TNM staging system is more complex, and it can give more precise information about the stage of your tumour.