Stage III is divided into stages IIIA, IIIB, and IIIC, depending on where the cancer has spread. In stage IIIC, cancer has spread (1) into the diaphragm, pleura (tissue that covers the lungs and lines the inner wall of the chest cavity), or sac around the heart. The cancer can be removed by surgery. Cancer is found in 1 to 6 lymph nodes near the tumor; or (2) into other nearby organs, such as the aorta, trachea, or spine, and the cancer cannot be removed by surgery; or (3) to 7 or more lymph nodes near the tumor.