For small cell lung cancers, doctors usually prefer to divide it into just two stages (limited and extensive), based on whether local treatments, such as surgery or radiation therapy may be helpful. The more formal TNM staging system (the same one used for non-small cell lung cancer) may also be used, but it's not as practical for small cell lung cancer. Here are the two stages:
Limited. In this stage, you have cancer only in one lung. There may also be cancer in nearby lymph nodes on the same side of your chest.
Extensive. If you have extensive stage cancer, the cancer has spread outside of the lung where it started. It may have spread to the other lung, to lymph nodes on the other side of the chest, or to distant parts of the body.