Stage IVA Lung Cancer AJCC v9

**Semantic type:** Neoplastic Process

**Definition:** Stage IVA includes: (Any T, Any N, M1a); (Any T, Any N, M1b); M1a: Metastasis in pleural or pericardial nodules, and/or malignant pleural or pericardial effusions, and/or separate tumor nodule(s) in a contralateral lobe. Note: Most pleural (pericardial) effusions with lung cancer are a result of the tumor. In a few patients, however, multiple microscopic examinations of pleural (pericardial) fluid are negative for tumor, and the fluid is non-bloody and not an exudate. If these elements and clinical judgment dictate that the effusion is not related to the tumor, the effusion should be excluded as a staging descriptor. M1b: Single extrathoracic metastasis in a single organ system (including involvement of a single non-regional node). (AJCC 9th ed.)