There are seven stages of non-small-cell lung cancer, including the hidden or occult stage, stage 0 or carcinoma in situ, and stages I, II, IIIA, IIIB and IV, which is the final phase, notes the National Cancer Institute. The process that doctors use to determine is cancer has spread throughout the lungs and to other areas of the body is known as staging. Staging determines the course of treatment for individual cancer cases.
Cancer initially develops in the hidden stage, which is known as the occult stage, notes the National Cancer Institute. Although hidden, bronchial washing or sputum analysis may reveal cancer cells. In stage 0, or carcinoma in situ the lining of the airways contains abnormal cells, some of which may spread to other body locations.
Stage I cancers are divided into two stages: IA and IB. In IA, the tumor is less than 3 centimeters in size and confined to the lung, while in stage IB, the lymph nodes are involved, the tumor is less than 5 centimeters, and the cancer has spread to the bronchus. In stage II, which is divided into two stages also, cancer continues to spread throughout the respiratory tract.
By stage IIIA, cancer may have spread to the chest wall, esophagus and trachea. Stage IV involves one or more tumors in both lungs and cancer cells may appear in the fluid around the heart and lungs. It also may have spread to the brain, kidneys and other parts of the body.