Doctors need to know which stage your lung cancer is in to help decide what treatment to recommend. The stage is based on these things:
Size and extent of your tumor
Whether there are lymph nodes involved and, if so, how many
Whether the cancer has spread to other parts of the body
Your oncologist gets this information from doing tests, such as CT scans.
The stages of non-small lung cancer are described using the TNM system.
The TNM system is a standard system for describing the extent of a cancer's growth. Here's what the letters stand for in the TNM system:
T tells how large a tumor is and whether it has grown into nearby structures.
N tells whether the lymph nodes near the tumor are cancerous.
M tells whether the cancer has spread (metastasized) to other organs in the body, such as your brain, bones, or liver.
Numbers are assigned to each of the T, N, and M categories. Once your oncologist has determined your T, N, and M stages, this information is put together in a stage grouping. Stage grouping is used to determine your overall disease stage.
These are the stages of non-small cell lung cancer. Each TNM category, with its assigned numerical value from X to 4, falls into one of these stages:
Occult. This means that there are cancer cells in your sputum, which is mucus from the lungs, or in other lung fluids. At this stage, the tumor in your lungs cannot be seen. You may hear your doctor use these TNM terms for this stage: TX, N0, M0.
Stage 0. In this stage, cancer is only in the cells lining your air passages. The cancer is very tiny. It has not invaded deeper into lung tissues or spread outside the lungs. Cancer at this stage is also called carcinoma in situ. You may hear your doctor use these TNM terms for this stage: Tis, N0, M0.
Stage I. In this stage, there is cancer in your lung, and it may affect your bronchi or the lining outside your lung. Cancer found at this stage usually offers a good chance of survival. Stage I is divided into Stage IA and IB based on the size and location of the tumor. For Stage IA, your doctor may use these TNM terms: T1, N0, M0. For Stage IB, your doctor may use these TNM terms: T2a, N0, M0.
Stage II. In this stage, the cancer may have spread into surrounding tissue, and there may be cancer in your lymph nodes within your lung on the same side the cancer is in. The tumor may be operable but may not be able to be completely removed. Stage II is divided into Stage IIA and IIB based on the size and location of the tumor and whether it has spread to the lymph nodes. For Stage IIA, your doctor may use these TNM terms: T1, N1, M0 or T2a, N1, M0 or T2b, N0, M0. For Stage IIB, your doctor may use these TNM terms: T2b, N1, M0 or T3, N0, M0.
Stage III. Stage III is divided into two substages: Stage IIIA and Stage IIIB. In Stage IIIA, the cancer may have spread to the organs or lymph nodes in the middle of the chest, called the mediastinum. Or it may have spread into a different lobe in the same lung. It may also have spread to lymph nodes behind your windpipe, called the trachea. For Stage IIIA, you may hear your doctor use these TNM terms: T1-T3, N2, M0 or T3, N1, M0 or T4, N0-N1, M0. In Stage IIIB, the cancer has spread to the lymph nodes above your collarbone on either side or to the lymph nodes on the other side of your chest, or it has grown into the middle part of the chest or into a different lobe of the same lung, as well as into lymph nodes in the middle of the chest. The tumor will likely not be able to be completely removed by surgery. For Stage IIIB, you may hear your doctor use these TNM terms: Any T, N3, M0 or T4, N2, M0.
Stage IV. In Stage IV, the cancer has spread to the other lung, into the fluid around the lung or heart, or to other distant organs in your body (such as the liver or brain). The tumor usually cannot be operated on. You may hear your doctor use these TNM terms for this stage: Any T, any N, M1a-M1b.