Definition

Stage IV non-small cell lung cancer is divided into stages IVA and IVB. In stage IVA, the tumor may be any size and cancer may have spread to the lymph nodes. One or more of the following is found: (1) there are one or more tumors in the lung that does not have the primary tumor; and/or (2) cancer is found in the lining around the lungs or the sac around the heart; and/or (3) cancer is found in fluid around the lungs or the heart; and/or (4) cancer has spread to one place in an organ not near the lung, such as the brain, liver, adrenal gland, kidney, or bone, or to a lymph node that is not near the lung. In stage IVB, cancer has spread to multiple places in one or more organs that are not near the lung.