Stage 3:
Stage three (III) lung cancers are classified as either stage IIIA or IIIB. For many stage IIIA cancers and nearly all stage IIIB cancers, the tumor is difficult, and sometimes impossible, to remove. For example, the lung cancer may have spread to the lymph nodes located in the center of the chest, which is outside the lung. Or, the tumor may have grown into nearby structures in the lung. In either situation, it is less likely that the surgeon can completely remove the cancer because removal of the cancer must be performed bit by bit.