What is lung cancer staging?

Staging is a way of defining how far the cancer has spread. Staging is important because the outline of your recovery and possible treatment depends on the stage of your cancer. For example, certain stages of cancer may be best treated with surgery, while others may be best treated with a combination of chemotherapy and radiation. Small cell and non-small cell lung cancers have different staging systems.

Treatment and prognosis (probable survival profile) for patients with lung cancer depend largely on the stage and cell type of the cancer. CT, MRI, scans, bone marrow biopsy, mediastinoscopy, and blood tests can be used to stage the cancer.

Be sure to ask your doctor to explain to you in a way that you can understand which stage you are in. This will tell you which decision path in this book is right for you. Reviewing these paths will help you and your doctor decide which treatment is best for your individual medical situation.

Staging of non-small cell lung cancer

The most commonly used staging system for describing the growth and spread of non-small cell lung cancer (NSCLC) is the TNM staging system, also called the American Joint Committee on Cancer (AJCC) system. In the TNM staging system, information about the tumor, nearby lymph nodes, and distant organ metastases is combined, and the stage is used to refer to a specific TNM grouping. The group stage is described using the number 0 and Roman numerals I to IV.

T stands for tumor (its size and how far it has spread within the lungs and nearby organs), N stands for lymph node spread, and M stands for metastasis (spread to distant organs).

NSCLC T staging: The T stage is based on the size of the lung cancer, its spread and location within the lungs, and the extent to which it has spread to nearby tissues.

1. Tis: The cancer is limited to the lining cells of the airway passages. It has not spread to other lung tissues. This stage of lung cancer is often called carcinoma in situ.

2. T1: The tumor is smaller than 3 cm (slightly less than 1 1/4 inches), has not spread to the visceral pleura (the membrane that surrounds the lungs), and has not affected the major bronchi.

3.T2: The cancer has one or more of the following characteristics:

(1) Larger than 3 cm

(2) Involves a major bronchus but is more than 2 cm (approximately 3/4 inch) from the carina (where the trachea divides into the left and right major bronchi).

(3) Has spread to the visceral pleura

(4) The cancer partially blocks the airway but does not cause total lung collapse or pneumonia

4.T3: The cancer has one or more of the following characteristics:

(1) Spread to the chest wall, diaphragm (the respiratory muscle that separates the chest from the abdomen), mediastinal pleura (the membrane that surrounds the space between the lungs), or parietal pericardium (the membrane that surrounds the heart).

(2) Involving one main bronchus, less than 2 cm (about 3/4 inch) from the carina (where the trachea divides into the left and right main bronchi) but not including the carina.

(3) It has grown into the airway sufficiently to cause total lung collapse or pneumonia.

5.T4: The cancer has one or more of the following characteristics:

(1) Spread to the mediastinum (the space behind the breastbone and in front of the heart), heart, trachea, esophagus (the tube connecting the throat and stomach), spine, or carina (where the trachea divides into the left and right main bronchi).

(2) There are two or more independent tumor nodules in the same lobe

(3) Having malignant pleural effusion (the fluid surrounding the lungs contains cancer cells).

N-stage of non-small cell lung cancer: The N stage depends on which nearby lymph nodes the cancer has invaded.

1. N0: The cancer has not spread to the lymph nodes

2. N1: The cancer has spread to lymph nodes only in the lungs and the hilar lymph nodes (located around where the bronchi enter the lungs). The metastatic lymph nodes are limited to the same side of the affected lung.

3. N2: Cancer has spread to the carinal lymph nodes (around the location where the trachea divides into the left and right bronchi) or mediastinal lymph nodes (the space behind the breastbone and in front of the heart). The involved lymph nodes are limited to the same side of the affected lung.

4. N3: Cancer has spread to the ipsilateral or contralateral supraclavicular lymph nodes and/or to the hilar or mediastinal lymph nodes on the contralateral side of the affected lung.

Non-small cell lung cancer grouping and staging: 1. Comprehensive staging: TNM staging

Stage 1.0: Tis (carcinoma in situ); N0; M0

2. Stage IA: T1; N0; M0

3. Stage IB: T2; N0; M0

4. Stage IIA: T1; N1; M0

5. Stage IIB: T2;N1;M0 or T3;N0;M0

6. Stage IIIA: T1; N2; M0 or T2; N2; M0 or T3; N1; M0 or T3; N2; M0

7. Stage IIIB: any T; N3; M0 or T4; any N; M0

8. Stage IV: Any T; Any N; M1

M stage of non-small cell lung cancer: The M stage depends on whether the cancer has spread to distant tissues or organs.

1.M0: No distant spread.

2. M1: The cancer has spread to one or more distant sites. Distant sites include other lung lobes, lymph nodes beyond those mentioned in the N stage above, and other organs or tissues, such as the liver, bones, or brain.

Staging groups for non-small cell lung cancer: Once the T, N, and M stages are known, this information is combined (staging groups) to give a comprehensive stage of 0, I, II, III, or IV (see Table 1). Patients with lower stages have a better survival outlook.

Staging of small cell lung cancer

Although small cell lung cancer can be staged like non-small cell lung cancer, most physicians find that the simpler 2-stage system provides better treatment options. This system divides small cell lung cancer into "limited stage" and "extensive stage" (also called diffuse stage).

Limited stage means the cancer is limited to one lung and the lymph nodes are only on that side of the chest.

If the cancer has spread to the other lung, to lymph nodes in the opposite chest, or to distant organs, or if there is malignant pleural effusion surrounding the lung, it is called extensive stage.