Stage 3A lung cancer includes tumors that are large and have spread to nearby lymph nodes, or tumors of any size that have spread to lymph nodes that are further away but still on the same side of the body as the cancer. The tumor may be any size and cancer may have spread to the main bronchus, the chest wall, the diaphragm, the pleura around the lungs, or the membrane around the heart, but cancer has not spread to the trachea; and part or the entire lung may have collapsed or developed pneumonitis. Stage 3A is considered a “locally advanced” cancer, meaning the tumor has not spread to distant regions of the body but has spread to lymph nodes on the same side of the body as the tumor.
Stage 3B lung cancer is a stage 3 lung cancer that is defined as a tumor of any size that has spread to distant lymph nodes, has invaded other structures such as the heart, major blood vessels that lead to or from the heart, the chest wall, the diaphragm, the trachea, the esophagus, the sternum (chest bone) or backbone, to more than one place in the same lobe of the lung, and/or into the fluid of the pleural cavity surrounding the lung. Stage 3B is considered advanced lung cancer along with stage 4, and though it is not usually curable, it is treatable.
Roughly 30% of people have stage 3 lung cancers at the time of diagnosis, leaving 30% of individuals diagnosed at an earlier stage and 40% having already progressed to stage 4 lung cancers at the time of diagnosis.
