Stage 3 lung cancer refers to advanced lung cancer where the tumor has spread beyond the lung to nearby lymph nodes and other surrounding tissues. There are two sub-stages of stage 3 lung cancer: 3A and 3B.

In stage 3A, the tumor may have spread to lymph nodes on the same side of the chest as the primary tumor or to the nearby structures like the chest wall or diaphragm.

In stage 3B, the tumor may have spread to lymph nodes on the opposite side of the chest or to distant organs such as the heart, trachea, or esophagus.

Treatment options for stage 3 lung cancer may include surgery, radiation therapy, chemotherapy, targeted therapy, immunotherapy, or a combination of these treatments, depending on the specific characteristics of the cancer and the overall health of the patient. The goal of treatment is to control the cancer, relieve symptoms, and prolong survival.