After a diagnosis of NSCLC, one of the first steps doctors will take is to try to determine the size of the cancer in the body and where it is located. This is called staging. As cancer spreads to new parts of the body, or metastasizes, it also increases in stage. There are 5 stages of NSCLC:

You may also see stages written in Roman numerals (I-IV). Some of these stages are further divided into sub-stages. It’s important to know what stage and sub-stage of lung cancer you have because it can help determine your treatment options.

There are options for testing and treatment for all different stages of lung cancer.

The stage of NSCLC is determined with TNM scores:

  • T - size of the tumour
  • N – measure of the spread of the cancer to the lymph nodes and how far
  • M - indicates if the cancer has spread or metastasized to other organs

The information below will help you better understand lung cancer and should not take the place of discussion with your healthcare team. Talking with them will help you fully understand your cancer diagnosis.

Stage 0 – Carcinoma in situ

What’s happening in the body: In situ means “in place” (i.e., the cancer is still located in the same place where it started). Cancer cells are found in the lining of the bronchi, but they have not invaded surrounding tissue. The cancer has not spread to the lymph nodes or other locations.

The goal for your healthcare team: Removing the tumour from the body. Surgery is a treatment for cancer that is found in the outer tissues of the lung in people who are healthy enough to have surgery, with removal of the tumour and a margin of healthy tissue. Radiation therapy can be used in people with poor lung function who cannot have surgery.

Stage 1 – Early-stage non-small cell lung cancer

What’s happening in the body: The cancer has not grown deeply into nearby tissues.

Stage 1 is further divided into two sub-stages: Stage 1A and Stage 1B

  • Stage 1A (T1; N0; M0): The cancer measures 3 cm or less and is contained within the lining of the lungs and chest cavity. Cancer has not spread to the lymph nodes or other locations.
  • Stage 1B (T2a; N0; M0): The tumour is larger than 3 cm and up to 4 cm in size; or  
    • - it involves the bronchus of the same lung (but not the trachea); or
    • - it has invaded the lining of the chest cavity; or
    • - it has blocked the airways causing a collapsed lung or inflammation.
    Cancer has not spread to the lymph nodes or other locations.

The goal for your healthcare team: Removing the tumour from the body through surgery is a treatment for people who are healthy enough to have surgery. Chemotherapy and/or radiation therapy can be offered to you for stage 1 NSCLC if you are not well enough to have surgery or if you choose not to have surgery. Your doctor will be able to determine the best treatment plan for you based on your specific cancer. You and your doctor will work closely together to figure out the best next steps.

Stage 2 – Early-stage NSCLC

What’s happening in the body: The tumour may have grown more deeply into nearby tissue and may also have spread to the lymph nodes but not to other parts of the body.

Stage 2 is further divided into two sub-stages: Stage 2A and Stage 2B  

  • Stage 2A (T2b; N0; M0): The tumour is larger than 4 cm and up to 5 cm; or
    • - it involves the bronchus of the same lung (but not the trachea); or
    • - it has invaded the lining of the chest cavity; or
    • - it has blocked the airways causing a collapsed lung or inflammation.
    Cancer has not spread to the lymph nodes or other locations.
  • Stage 2B (T1 or T2; N1; M0): The tumour is no larger than 5 cm and it:
    • - may involve the bronchus of the same lung (but not the trachea); or
    • - may have involved the lining of the chest cavity; or
    • - may have blocked the airways causing a collapsed lung or inflammation.
    The cancer has spread to nearby lymph nodes but not to other locations; or
  • Stage 2B (T3; N0; M0): The tumour is larger than 5 cm and up to 7 cm in size; or there is more than one tumour in the same lobe; or it has invaded the chest wall or its inner lining, the main nerve to the diaphragm (phrenic nerve), or the lining of the heart (parietal pericardium).
    The cancer has not spread to the lymph nodes or other locations.

The goal for your healthcare team: At this stage, the tumour can be removed by surgery, which is a treatment for people who are healthy enough to have surgery. The type of surgery will depend on the location of the tumour. Lymph nodes in the chest and around the lungs are also removed and checked for the presence of cancer. Chemotherapy may be recommended after surgery. Radiation therapy is an option if you are not well enough to have surgery or if you choose not to have surgery. You can have radiation therapy after surgery if cancer is found in the margins of the removed tissue and you are no longer a candidate for surgery. Your doctor will be able to determine the best treatment plan for you based on your specific cancer. You and your doctor will work closely together to figure out the best next steps.

Stage 3 – Locally advanced NSCLC

What’s happening in the body: The cancer has grown more deeply into nearby tissue. It may have also spread to lymph nodes but not to other distant parts of the body.

Stage 3A

  • Stage 3A (T1 or T2; N2; M0): The tumour is no larger than 5 cm. The cancer may involve the bronchus of the same lung (but not the trachea); or may have invaded the lining of the chest cavity; or may have blocked the airways causing a collapsed lung or inflammation.
    The cancer has spread to lymph nodes near the centre of the chest but not to other locations; or
  • Stage 3A (T3; N1; M0): The tumour is larger than 5 cm and up to 7 cm in size; or there is more than one tumour in the same lobe; or it has invaded the chest wall or its inner lining, the main nerve to the diaphragm (phrenic nerve), or the lining of the heart (parietal pericardium).
    The cancer has spread to nearby lymph nodes but not to other locations; or
  • Stage 3A (T4; N0 or N1; M0): The tumour is larger than 7 cm; or there is more than one tumour in different lobes of the same lung; or it has invaded the diaphragm, mediastinum, heart or its large blood vessels, trachea, the main nerve to the voice box (recurrent laryngeal nerve), esophagus, or spine.
    The cancer may have spread to nearby lymph nodes but not to other locations.

Stage 3B

  • Stage 3B (T1 or T2; N3; M0): The tumour is up to 5 cm in size. The cancer may involve the bronchus of the same lung (but not the trachea); or it may have invaded the lining of the chest cavity; or may have blocked the airways causing a collapsed lung or inflammation. The cancer has spread to lymph nodes near the other lung or to those near the collarbones. But it has not spread to other locations; or
  • Stage 3B (T3 or T4; N2; M0): The tumour is larger than 5 cm; or there is more than one tumour in the same lung. The cancer may have invaded the chest wall or its inner lining, mediastinum, trachea, esophagus, spine, diaphragm, the main nerves to the diaphragm (phrenic nerve) or the voice box (recurrent laryngeal nerve); the heart, its large blood vessels, or its lining (parietal pericardium).
    The cancer has spread to lymph nodes near the centre of the chest but not to other locations.

Stage 3C

  • Stage 3C (T3 or T4; N3; M0): The tumour is larger than 5 cm; or there is more than one tumour in the same lung. The cancer may have invaded the chest wall or its inner lining, mediastinum, trachea, esophagus, spine, diaphragm, the main nerves to the diaphragm (phrenic nerve) or to the voice box (recurrent laryngeal nerve); the heart, its large blood vessels, or its lining (parietal pericardium).
    The cancer has spread to lymph nodes near the other lung or to those near the collarbones but not to other locations.

The goal of treatment: For people with Stage 3 NSCLC, treatment is usually a combination of chemotherapy radiation therapy possibly followed by surgery to remove the tumour. In most cases, chemotherapy and radiation are given on the same day; however, there may be cases where they are given sequentially (one after the other) on different days. Immunotherapy and Targeted Therapy options may also be used at this stage. Biomarker testing is a critical step in the diagnosis as it helps guide to the suitable treatment options. Your doctor will be able to determine the best treatment plan for you based on your specific cancer. You and your doctor will work closely together to figure out the best next steps.

Stage 4 – Metastatic NSCLC

What’s happening in the body: Stage 4 lung cancer is the most advanced form of the disease. In Stage 4, the cancer is called metastatic, which means the cancer has spread away from the lungs, to other organs or parts of the body, such as the liver or other organs, or to fluid in the areas around the lungs or the heart.

Stage 4 is split into two substages: Stage 4A and Stage 4B

Stage 4 – Metastatic NSCLC

  • Stage 4A (Any T; any N; M1a or M1b): The tumour is of any size. The cancer has spread to the other lung or to a single location outside the chest cavity—for example, the liver, adrenal glands, brain, or bones; or fluid containing cancer cells has collected around the lung (pleural effusion) or heart (pericardial effusion). The cancer may have invaded other tissues, structures, and lymph nodes in the chest.
  • Stage 4B (Any T; any N; M1c): The tumour is of any size. The cancer has spread to multiple locations outside the chest cavity—for example, the liver, adrenal glands, brain, or bones. The cancer may have invaded other tissues, structures, and lymph nodes in the chest.

The goal for your healthcare team: Treatments like surgery, chemotherapy and/or radiation therapy, targeted therapy, and immunotherapy may be recommended. Biomarker testing is a critical step in the diagnosis as it helps guide to the suitable treatment options. Talk to your doctor to decide which treatment option may be right for your specific type of lung cancer.