What is staging of lung cancer

The stage of a cancer refers to the extent to which a cancer has spread in the body. Staging involves both evaluation of a cancer'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 cancer should be treated, since lung-cancer therapies are geared toward specific stages. Staging of a cancer is also critical in estimating the prognosis of a given patient, with higher-stage cancers generally having a worse prognosis than lower-stage cancers.

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 cancer 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 from the chest to other parts of the body.

SCLC are staged using a two-tiered system:

* Limited-stage SCLC refers to cancer that is confined to its area of origin in the chest.

* In extensive-stage SCLC, the cancer has spread beyond the chest to other parts of the body.