Lung cancer may be staged once or twice. The first staging, which all patients should undergo, is carried out when a patient is initially diagnosed; it should be completed before treatment begins. This type of staging is called clinical staging. Clinical staging is based on the results of various tests, including imaging tests and biopsies. The clinical stage is not only the basis for deciding on a patient’s treatment plan, but is also the basis for comparison when checking into the patient’s response to treatment.

The second staging called pathologic or surgical staging, adds what is learned about the patient’s cancer from surgical treatment to the determination of staging. If the pathologic stage differs from the clinical stage (which it may, for example, if it is evident that the lung cancer has spread more than initially estimated), then the healthcare team can adjust the treatment more precisely.

The TNM staging system is used for non-small cell lung cancer (NSCLC). Including lung adenocarcinoma, squamous cell lung cancer, and large cell lung cancer. The same system can also be used for small cell lung cancer, although for small cell lung cancer a two stages only system, limited-stage and extensive-stage, is more often used.

Stages using TNM classifications are designated by a number, zero (0) through four. For one through four, the Roman numerals I through IV are used. The lower the stage number, the less advanced the cancer is and the better the outcome is likely to be; the higher the stage number, the more advanced the cancer is. Stages I-IV are further divided into substages.

Lung cancer Stage 0

• This is called “in situ” disease, meaning that the cancer is “in place” and has not invaded or spread from where it first developed.

Lung cancer Stage I

• Stage I lung cancer tumors are small primary tumors that are in one lung only. Stage I lung cancer has not spread to any lymph nodes and has not metastasized. Stage I lung cancer is divided into two substages: stage IA and stage IB, based mainly on the size of the tumor.
  Smaller tumors, those no more than 3 centimeters (cm) in the greatest dimension, are stage IA, while slightly larger ones—more than 3 cm but no more than 4 cm in the greatest dimension—are stage IB. Stage IB tumors may or may not have grown into the main bronchus or the lung’s inner lining or have caused lung collapse or swelling.

Lung cancer Stage II

• Like stage I lung cancer, stage II lung cancer is located in the lung where it has started. Stage II lung cancers have not metastasized to distant parts of the body. Stage II lung cancer is divided into two stages: Stage IIA and stage IIB. Stage IIA tumors are more than 4 cm but no more than 5 cm in the greatest dimension and have not spread to nearby lymph nodes. The tumors may or may not have grown into the main bronchus or into the lung’s inner lining, or have caused lung collapse or swelling.

Lung cancer Stage III

• Stage III lung cancer has spread within the chest but has not metastasized to distant parts of the body. It is sometimes referred to as locally advanced. Stage III lung cancer is divided into three stages: stage IIIA, stage IIIB, and stage IIIC.

Stage IIIA tumors are either:

• More than 7 cm in the greatest dimension and have not spread to nearby lymph nodes. They may have grown into the diaphragm, mediastinum, heart or its major blood vessels, windpipe, recurrent laryngeal nerve, carina, esophagus, or spine, or there are secondary tumors in the same lung but a different lobe than the primary tumor.
• More than 5 cm in the greatest dimension and have spread to the peribronchial nodes and/or to the hilar and intrapulmonary nodes of the lung with the primary tumor. The tumors have grown into the lung’s outer lining or nearby sites, including the chest wall of the heart’s lining, or there are primary or secondary tumors in the same lobe; and/or tumors have grown into the diaphragm, mediastinum, heart or its major blood vessels, windpipe, recurrent laryngeal nerve, carina, esophagus, or spine, or there are secondary tumors in the same lung but a different lobe than the primary tumor

Stage IIIB tumors are either:

• More than 5 cm in the greatest dimension and have spread to mediastinal lymph nodes, which include subcarinal nodes, near the lung with the primary tumor. Tumors have grown into the lung’s outer lining or nearby sites, including the chest wall, phrenic nerve, or the heart’s lining, or there are primary or secondary tumors in the same lobe; and/or tumors have grown in the diaphragm, mediastinum, heart or its major blood vesels, windpipe, recurrent laryngeal nerve, carina, esophagus, or spine, or there are secondary tumors in the same lung but a diferent lobe than the primary tumor.
• Stage IIIC tumors are more than 5 cm in the greatest dimension and have spread to mediastinal or hilar nodes near the lung without the primary tumor, or to any supraclavicular, or scalene, lymph nodes. Tumors have grown into the lung’s outer lining or nearby sites, including the chest wall, phrenic nerve, or the heart’s lining, or there are primary or secondary tumors in the same lobe, and/or tumors have grown into the diaphragm, mediastinum, heart or its major blood vessels, windpipe, recurent laryngeal nerve, carina, esophagus, or spine, or there are secondary tumors in the same lung but a different lobe than the primary tumor.

Lung cancer IV

Unlike the earlier stages of lung cancer, stage IV lung cancer has metastasized to distant parts of the body. The tumors may be of any size and may or may not have spread to lymph nodes. Stage IV lung cancer is divided into two stages: stage IVA and stage IVB.

• Stage IVA tumors have metastasized, either from one lung into the other lung, into the lung’s lining (and have formed secondary nodules), into the heart’s lining (and have formed secondary nodules), or into the fluid around the lungs or the heart; and/or tumors have spread to one site outside the chest area (e.g., adrenal gland or bones).
• Stage IVB tumors have metastasized to multiple sites outside the chest area (e.g., adrenal gland and bones).

Recurrence

Recurrent lung cancer is lung cancer that has come back after treatment. If there is a recurrence, the cancer may need to be staged again (“restaged”) using the system described above.