Stage IA1

**Semantic type:** Clinical Attribute

**Definition:** A stage term referring to invasive cervical and lung cancer. For cervical cancer, it includes: T1a1, N0, M0. T1a1: Tumor with stromal invasion 3.0 mm or less in depth and 7.0 mm or less in horizontal spread. N0: No regional lymph node metastasis. M0: No distant metastasis. For lung cancer, it 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. A superficial, spreading tumor of any size whose invasive component is limited to the bronchial wall and may extend proximal to the main bronchus also is classified as T1a, but these tumors are uncommon. N0: No regional lymph node metastasis. M0: No distant metastasis. (adapted from AJCC)