Staging for small cell lung cancer

Staging is the process of finding out how far the cancer has spread. This is very important because your treatment and your outlook (prognosis) depend on the stage of the cancer. The tests described in the section, "How is small cell lung cancer found?" are also used to stage lung cancer.

A staging system is a standard way for doctors to describe how large a cancer is and how far it has spread. There are 2 types of staging.

The clinical stage is based on the results of the physical exam, biopsies, and imaging tests (CT scan, chest x-ray, PET scan, etc.).

If you have surgery, your doctor can also determine a pathologic stage, which is based on the same factors as the clinical stage, plus what is found during the surgery.

The clinical and pathologic stages may be different in some cases. During surgery the doctor may find cancer in a place that did not show up on imaging tests. That could mean a more advanced pathologic stage. Because most patients with lung cancer do not have surgery, the clinical stage is most often used when describing the cancer.

Small cell lung cancer staging systems

There are 2 staging systems that can be used to describe the spread of small cell lung cancer.

Limited vs. extensive stage

For small cell lung cancer a 2-stage system is most often used. This system divides small cell lung cancers into limited stage or extensive stage.

Limited stage usually means that the cancer is only in one lung and perhaps in lymph nodes on the same side of the chest. The cancer is most often confined to an area that is small enough to be treated with radiation.

If the cancer has spread to the other lung, to lymph nodes on the other side of the chest, or to distant organs, it is called extensive. Many doctors also call cancer that has spread to the fluid around the lung extensive stage.

Small cell lung cancer is staged in this way because it helps to separate people who may be helped by treatments such as surgery and radiation therapy to try to cure the cancer (limited stage) from those for whom these treatments aren't likely to cure the cancer (extensive stage).

The TNM staging system

A more formal system to describe the growth and spread of lung cancer is the American Joint Committee on Cancer (AJCC) TNM staging system. Stages are described using Roman numerals from 0 to IV (0 to 4). Some stages are further divided into A and B. As a rule, the lower the number, the less the cancer has spread. A higher number, such as stage IV (4), means a more advanced cancer.

This system is used more often for non-small cell lung cancer. It is used less often for small cell lung cancer, mainly because treatment options don't vary much between these detailed stages.