Staging is a very important part of the lung cancer diagnosis process. The stage finds out if and to what extent the lung cancer has spread from its original location. Knowing the stage will help your oncologist best shape your treatment plan.

The staging system most often used for lung cancer is the American Joint Committee on Cancer (AJCC) TNM system, which is based on 3 key pieces of information:

  • The size and extent of the main tumor (T)
  • The spread to nearby (regional) lymph nodes (N)
  • The spread (metastasis) (M) to other organs of the body

The information gathered from the staging process gives the oncologist a better idea regarding the seriousness of the cancer, what treatments will be the most effective, if there are clinical trials for viable treatment options, and your chances of survival (prognosis).

After determining a diagnosis of small cell lung cancer (SCLC) or non-small cell lung cancer (NSCLC), additional testing determines if the cancer cells have spread (metastasized) within the chest or to other parts of the body. This information determines the stage of the disease and treatment plan.

Staging Small Cell Lung Cancer

Tests and procedures that may be used to stage small cell lung cancer include:

  • Laboratory tests
  • Bone marrow aspiration and biopsy: A procedure in which a small sample of bone marrow is removed with a hollow needle, usually from the hip bone, breastbone, or thigh bone. A pathologist views them under a microscope to look for signs of cancer.
  • MRI (magnetic resonance imaging)
  • Endoscopic ultrasound (EUS)
  • Lymph node biopsy: The removal of all or part of a lymph node so a pathologist can look for signs of cancer cells under a microscope.
  • Radionuclide bone scan

Stages of Small Cell Lung Cancer

Small cell lung cancer falls under one of two categories:

  • Limited: cancer is found in one lung, the tissues between the lungs, and nearby lymph nodes only.
  • Extensive: cancer has spread outside of the lung in which it began or to other parts of the body.

Staging Non-Small Cell Lung Cancer

Additional tests and procedures that may be used in the non-small cell lung cancer staging process include:

  • Lymph node biopsy
  • Mediastinoscopy: A surgical procedure in which a mediastinoscope is used to examine the organs in the area between the lungs and nearby lymph nodes for cancer. A mediastinoscope is a thin, tube-like instrument with a light and a lens for viewing. It is inserted into the chest through an incision (cut) made at the top of the breastbone.
  • Anterior mediastinotomy: A surgical procedure to look at the organs and tissues between the lungs and between the breastbone and heart for abnormal areas. This is also called the Chamberlain procedure.

Stages of Non-Small Cell Lung Cancer:

Because staging for NSCLC can be complex, it is important to ask your oncologist to explain it in a way that’s easy to understand. The stages of NSCLC are as follows:

Occult (hidden) stage

In the occult (hidden) stage, cancer cells are found in sputum (mucus coughed up from the lungs), but no tumor can be found in the lung by imaging or bronchoscopy, or the primary tumor is too small to be checked.

Stage 0 (Carcinoma in Situ)

In stage 0, abnormal cells are found in the innermost lining of the lung. These abnormal cells may become cancerous and spread into nearby normal tissue. Stage 0 is also called carcinoma in situ (localized).

Stage I

Cancer has formed. Stage I is divided into stages IA and IB:

Stage IA
The tumor is in the lung only and is 3 centimeters or smaller.

Stage IB
One or more of the following is true:

  • The tumor is larger than 3 centimeters.
  • Cancer has spread to the main bronchus of the lung, and is at least 2 centimeters from the carina (where the trachea joins the bronchi).
  • Cancer has spread to the innermost layer of the membrane that covers the lungs.
  • The tumor partly blocks the bronchi or bronchioles and part of the lung has collapsed or developed pneumonitis (inflammation of the lung).

Stage II

Stage II is divided into stages IIA and IIB:

Stage IIA
The tumor is 3 centimeters or smaller and cancer has spread to nearby lymph nodes on the same side of the chest as the tumor.

Stage IIB
Cancer has spread to nearby lymph nodes on the same side of the chest as the tumor and one or more of the following is true:

  • The tumor is larger than 3 centimeters.
  • Cancer has spread to the main bronchus of the lung and is 2 centimeters or more from the carina (where the trachea joins the bronchi).
  • Cancer has spread to the innermost layer of the membrane that covers the lungs.
  • The tumor partly blocks the bronchi or bronchioles and part of the lung has collapsed or developed pneumonitis (inflammation of the lung).

​OR

Cancer has not spread to lymph nodes and one or more of the following is true:

  • The tumor may be any size, and cancer has spread to the chest wall, or the diaphragm, or the pleura between the lungs, or membranes surrounding the heart.
  • Cancer has spread to the main bronchus of the lung and is no more than 2 centimeters from the carina (where the trachea meets the bronchi), but has not spread to the trachea.
  • Cancer blocks the bronchi or bronchioles, and the whole lung has collapsed or developed pneumonitis (inflammation of the lung).

Stage III

Stage III is divided into stages IIIA and IIIB:

Stage IIIA
Cancer has spread to lymph nodes on the same side of the chest as the tumor. The tumor may be any size. One or more of the following is true:

  • Cancer may have spread to the main bronchus, the chest wall, the diaphragm, the pleura around the lungs, or the membrane around the heart, but has not spread to the trachea.
  • Part or all of the lung may have collapsed or developed pneumonitis (inflammation of the lung).

Stage IIIB

The tumor may be any size and has spread:

  • To lymph nodes above the collarbone or in the opposite side of the chest from the tumor; and/or to any of the following:
  • Heart
  • Major blood vessels that lead to or from the heart
  • Chest wall
  • Diaphragm
  • Trachea
  • Esophagus
  • Sternum (chest bone) or backbone
  • More than one place in the same lobe of the lung
  • The fluid of the pleural cavity surrounding the lung

Stage IV

In Stage IV, cancer may have spread to lymph nodes and has spread to another lobe of the lungs or to other parts of the body, such as the brain, liver, adrenal glands, kidneys, or bone.