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.
Patients with stage I disease have a significantly better prognosis than those with more advanced stages. Because of the relative rarity of this disease, exact survival information based upon stage is limited.
Definitions of TNM
The American Joint Committee on Cancer has designated staging by TNM classification to define malignant mesothelioma.
International Mesothelioma Interest Group Staging System for Diffuse Malignant Pleural Mesothelioma