Cancer staging is a term used to refer to describing the tumor's size and position and whether or not it has spread beyond the area where it began. Knowledge of a tumor's stage helps doctors decide on the best treatment.

Doctors use the same staging system for small-cell lung cancer and non-small cell lung cancers. This system looks at:

  • tumor size
  • whether it has spread to nearby parts of the lung or outside of the lung
  • whether there is cancer in the nearby lymph nodes, in the chest, or in further-away parts of the body
  • whether it has spread to other parts of the body

Stage 1

The cancer is not bigger than 5 cm. It is inside the lung (localized) and not in the lymph nodes. This is early or localized lung cancer.

Stage 2

The cancer is not larger than 7 cm and may have spread to nearby lymph nodes or not.


The cancer is larger than 7 cm in size and has not spread to the lymph nodes, though is it larger and larger in other parts of the lung or the airway or areas outside of the lung.

Stage 3

The cancer may be of any size but has spread to lymph nodes located further away from its point of origin.

The cancer may also be growing in other parts of the lung, the airway, or in other areas outside of the vicinity of the lung.

The cancer may also have spread to tissues and structures further away from the lung. However, the cancer has not spread to other parts of the body.

Stage 2 and 3 cancers are called locally advanced cancer.

Stage 4

The cancer may be of any size, may have spread into the lymph nodes and one of the following:

The cancer has spread to the lung on the other side.

There are cancer cells in the fluid of the pleura or around the heart.

The cancer has spread to other parts of the body such as the liver, bones, or brain.

Stage-4 cancer is called metastatic cancer.

Small-cell lung cancer

Doctors can divide small-cell lung cancers into two stages:

  • Limited-stage disease – the cancer cells can be seen in one lung and in the nearby lymph nodes.
  • Extensive-stage disease – the cancer has spread outside of the lung to the chest area or other parts of the body.

Small-cell lung cancers are given more intense treatment because they are more biologically aggressive even when the disease is in in a limited stage.