TNM staging
The descriptors of the TNM staging system are:
T stands for TUMOUR — and indicates the size of the tumour and the depth of any tumour invasion into the lung.
N stands for NODES — indicates if the tumour has spread to nearby lymph nodes.
M stands for METASTASIS — and indicates whether the cancer has spread to other parts of the body..
Once the T, N, and M categories have been determined, this information is combined in a process called stage grouping to assign an overall stage.
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Stage I
Cancer cells are limited to the lung. Tissue around the lung remains normal.
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Stage II
Cancer has spread to nearby lymph nodes or the lining of the lungs. Depending on the tumour size, stage ll is divided into IIA and IIB.
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Stage III
Cancer has spread to the lymph nodes in the centre of the chest between the heart and lungs (the mediastinum) or has grown into the chest wall or the outer lining that surrounds the heart (the pericardium). Blood vessels in this area may also be affected. Or, cancer is found in the lymph nodes on the opposite side of the chest where the tumour fist developed. Cancer may also have spread to the lower neck.
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Stage IV
Cancer has spread to the other lung, found in fluid around the heart or lung, or spread to other parts of the body. This includes distant lymph nodes or to other organs such as bones, liver and brain.