Stage IA1 Lung Cancer AJCC v9

**Semantic type:** Neoplastic Process

**Definition:** Stage IA1 includes: (T1mi, N0, M0); (T1a, N0, M0). T1mi: Minimally invasive adenocarcinoma: adenocarcinoma (3 cm or less in greatest dimension) with a predominantly lepidic pattern and 5 mm or less invasion in greatest dimension. T1a: Tumor measuring 1 cm or less in greatest dimension or tumor of any size whose invasive component is limited to the bronchial wall and may extend proximal to the main bronchus, but this is an uncommon superficial spreading tumor. N0: No tumor involvement of regional lymph node(s). M0: No distant metastasis. (AJCC 9th ed.)