Stage III lung cancer is cancer that has progressed to the point that the tumor is difficult or impossible to remove through surgery, according to the American Society of Clinical Oncology. The tumor may have spread to a nearby organ or to the lymph nodes around the chest.
Stage III lung cancer is divided into two categories, IIIA or IIIB, depending on where the tumor is located and how large it is, according to Cancer Treatment Centers of America. In some IIIA cancers and nearly all IIIB cancers, removal of the tumor is rarely successful, according to the ASCO. There are still treatment options available, which the doctor discusses with the patient after taking several factors into consideration, including physical health and pre-existing conditions.