Stage I non-small cell lung cancer ( sel lung KAN-ser)

Stage I is divided into stages IA and IB. In stage IA, the tumor is in the lung only and is 3 centimeters or smaller. In stage IB, one or more of the following is true: (1) the tumor is larger than 3 centimeters; (2) cancer has spread to the main bronchus of the lung, and is at least 2 centimeters from the carina (where the trachea joins the bronchi); (3) cancer has spread to the innermost layer of the membrane that covers the lungs; and/or (4) the tumor partly blocks the bronchus or bronchioles and part of the lung has collapsed or developed pneumonitis (inflammation of the lung).