Stages of Lung Cancer

What is staging of lung cancer?

The stage of a tumor refers to the extent to which a 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, since lung cancer therapies are geared toward specific tumor stages. Staging of a tumor is also critical in estimating the prognosis of a given patient, with higher-stage tumors generally having a worse prognosis than lower-stage tumors.

Doctors may use several tests to accurately stage a lung cancer, including laboratory (blood chemistry) tests, x-rays, CT scans, bone scans, and MRI scans. Abnormal blood chemistry tests may signal the presence of metastases in bone or liver, and radiological procedures can document the size of a tumor as well as possible spread to other organs.

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 chest (with larger and more invasive tumors classified as stage III).
• Stage IV cancer has spread away from the chest to other parts of the body.

SCLC are staged using a two-tiered system:

• Limited stage (LS) SCLC refers to cancer that is confined to its area of origin in the chest.
• In extensive-stage (ES) SCLC, the cancer has spread beyond the chest to other parts of the body.