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The stage of a cancer describes how far it has spread. This is very important because your treatment and your outlook (prognosis) depend largely on the stage of the cancer. The exams and tests described in the section “How is small cell lung cancer found?” are also used to stage lung cancer.

Small cell lung cancer staging systems

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 staging systems that can be used to describe the spread of small cell lung cancer (SCLC).

Limited vs. extensive stage

For treatment purposes, a 2-stage system is most often used. This system divides SCLC 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 one radiation “port.” Only about 1 out of 3 people have limited stage SCLC when it is first found.

Extensive stage means the cancer has spread widely throughout a lung, to the other lung, to lymph nodes on the other side of the chest, or to distant organs. Many doctors also call cancer that has spread to the fluid around the lung extensive stage. About 2 out of 3 people with SCLC have extensive disease when their cancer is first found.

SCLC is staged in this way because it helps to separate people who may be helped by more aggressive treatments such as chemotherapy combined with radiation therapy to try to cure the cancer (limited stage) from those for whom chemotherapy alone is likely to be a better option (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. It is based on 3 key pieces of information:

  • The size of the main tumor and whether it has grown into nearby areas
  • Whether the cancer has reached nearby lymph nodes
  • Whether the cancer has spread to other parts of the body

Stages are described using the number zero and Roman numerals from I 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.

For more details the staging of lung cancer, see “How is small cell lung cancer staged?” in our document Lung Cancer (Small Cell).

Last Medical Review: 09/09/2014
Last Revised: 01/19/2016