Soon after your diagnosis, your treating doctors will “stage” your cancer. This is the process of determining how advanced your cancer is – namely, how large the tumour is, where it is located and if it has spread to another area of the body. This may involve more scans and procedures. What stage your cancer is at will help to determine your treatment plan.

The internationally agreed system for lung cancer staging is called “TNM” – this stands for Tumour, Node, Metastasis.

  • Tumour – its size and where it is located.
  • Node – whether there is regional lymph node involvement.
  • Metastasis – if and where the cancer has spread beyond its original site.

Both non-small cell lung cancer and small cell lung cancer are staged using the TNM staging system. Below is a broad overview of the different stages. Sub-classification can exist within each stage (e.g., A/B/C), which is dependent on the size, location and spread of the tumour.

Stage I

  • This means the cancer cells are confined to the lung but the surrounding tissues remain normal.

Stage II

  • The tumour has grown in size and/or there has been some spread of the cancerous cells, either to the nearby lymph nodes and/or the lining of the lungs.

Stage III

  • This stage indicates moderate spread of the cancer, usually to the lymph nodes in the mediastinum (the area in the chest between the lungs). It may also have grown into the chest wall or the outer lining that surrounds the heart (the pericardium), or surrounding blood vessels might be affected.

Stage IV

  • This stage means the cancer has metastasised, or spread, to the lining of the lung or other parts of the body. This could include distant lymph nodes or other organs such as the bones, liver and brain.

Stage I and Stage II cancers would be classified as early-stage disease. Stage IV is the most advanced stage of lung cancer.