What is staging of lung cancer?

The stage of a tumor refers to the extent to which lung cancer has spread in the body. Staging involves both evaluation of a tumor's size as well as the presence or absence of metastases in the lymph nodes or in other organs. Staging is important for determining how a particular tumor should be treated. Staging of a tumor is also critical in estimating the prognosis of a given patient, with higher-stage tumors having a worse prognosis than lower-stage tumors.

Doctors use several tests to accurately stage lung cancer, including blood tests, X-rays, CT scans, bone scans, and PET scans. An abnormal blood chemistry test may signal the presence of metastases in the bone or liver. Radiological procedures document the size of a tumor, as well as its spread to other organs.

Non-small cell lung cancers (NSCLC) are assigned a stage from I to IV in order of severity.

• In stage I, the cancer is confined to the lung.
• In stages II and III, the cancer is confined to the lung and, possibly, the lymph nodes.
• Stage IV cancer has spread outside of the lung to other parts of the body.

Small cell lung cancers (SCLC) are staged using a two-tiered system: