Lung Cancer Staging
Staging is a way of defining how far the cancer has spread. Staging is important because the possible profile of your recovery and treatment depends on the stage of your cancer. For example, a certain stage of cancer may be best treated with surgery, while others are best treated with a combination of chemotherapy and radiation. The staging systems for small cell and non-small cell lung cancer are not the same.
The treatment and prognosis (probable survival profile) of patients with lung cancer depends greatly on the stage and cell type of the cancer. CT, MRI, scans, bone marrow biopsies, mediastinoscopy and hematology tests are available for staging the cancer.
Be sure to have your doctor explain to you in a way that you can understand what stage you are in. This will tell you which of the decision pathways in this book is right for you. Reviewing these pathways will help you and your doctor decide together which treatment is best for your individual medical situation.
Staging of non-small cell lung cancer
The most common way to describe the growth and spread of non-small cell lung cancer (NSCLC) is the TNM staging system, also called the American Joint Committee on Cancer system (AJCC). In TNM staging, information about the tumor, nearby lymph nodes, and distant organ metastases is combined, and staging is used to refer to specific TNM subgroups. Subgroup staging is described using the number 0 and Roman numerals I through IV.
T stands for tumor (its size and extent of spread within the lung and adjacent organs), N stands for lymph node spread, and M stands for metastasis (spread to distant organs).
T-stage of non-small cell lung cancer: T grading is based on the size of the lung cancer, its spread and location within the lung, and the extent of spread to adjacent tissues.
Tis: Cancer is confined to the inner cells of the airway pathways. It has not spread to other lung tissues, and this stage of lung cancer is usually also called carcinoma in situ.
T1: The tumor is less than 3 cm (slightly less than 11/4 inches), has not spread to the dirty pleura (the membrane that surrounds the lung), and has not affected the major bronchi.
T2: Cancer with one or more of the following characteristics.
Larger than 3 cm
Involves a major bronchus but is more than 2 cm (about 3/4 inch) from the bullae (where the trachea divides into the right and left major bronchi).
Has spread to the dirty pleura
The cancer has partially blocked the airway but has not caused total lung atrophy or pneumonia
T3: The cancer has one or more of the following characteristics.
Spread to the chest wall, diaphragm (the breathing muscle that separates the chest from the abdomen), mediastinal pleura (the membrane that wraps around the space between the two lungs), or mural pericardium (the membrane that wraps around the heart).
Involvement of one side of the main bronchus less than 2 cm (about 3/4 inch) from the bullae (where the trachea divides into the right and left main bronchus) but not containing the bullae.
Has grown into the airway enough to cause total lung atrophy or total pneumonia.
T4: Cancer with one or more of the following characteristics.
Has spread to the mediastinum (the space in front of the heart behind the sternum), heart, trachea, esophagus (the tube that connects the larynx to the stomach), spine, or ramus (the place where the trachea divides into the right and left main bronchi).
Two or more separate tumor nodules in the same lung lobe
Have malignant pleural fluid (fluid that contains cancer cells in the fluid that surrounds the lung).
N grading of non-small cell lung cancer: N staging depends on which nearby lymph nodes the cancer has invaded.
N0: cancer has not spread to the lymph nodes
N1: The lymph nodes where the cancer has spread are limited to the intrapulmonary, hilar lymph nodes (located around where the bronchi enter the lung). The metastatic lymph nodes are limited to the ipsilateral side of the affected lung.
N2: The cancer has spread to the ramus lymph nodes (around the location where the trachea divides into the right and left bronchi) or mediastinal lymph nodes (the space in front of the heart behind the sternum). The involved lymph nodes are limited to the ipsilateral side of the affected lung.
N3: The cancer has spread to the ipsilateral or contralateral supraclavicular lymph nodes and/or spread to the hilar or mediastinal lymph nodes contralateral to the affected lung.
M-stage of non-small cell lung cancer: M-stage depends on whether the cancer has metastasized to distant tissues or organs.
M0: There is no distant spread.
M1: The cancer has spread to one or more distant sites. Distant sites include other lung lobes, lymph nodes beyond those mentioned in N stage above, and other organs or tissues such as liver, bone or brain.
Staging of non-small cell lung cancer: Once T, N, and M stages are defined, the combination of these information (staging grouping) can be used to define a combined stage 0, I, II, III, or IV (see Table 1). Patients with lower staging have better survival prospects.
Staging of small cell lung cancer
Although small cell lung cancer can be staged like non-small cell lung cancer, the vast majority of physician practitioners find the simpler stage 2 system to be better in terms of treatment options. This system divides small cell lung cancer into “limited” and “extensive” (also known as diffuse) stages.
Limited stage means that the cancer is confined to one lung and the lymph nodes are located only on the same side of the chest.
If the cancer spreads to the other lung, or to lymph nodes in the opposite chest, or to distant organs, or if malignant pleural fluid surrounds the lung, then it is called extensive.