Stage IA

**Semantic type:** Clinical Attribute

**Definition:** Invasive cancer confined to the original anatomic site of growth without lymph node involvement. The definition of stage IA depends on the particular type of cancer that it refers to; for example, for breast cancer, stage IA is defined as follows: T1, N0, M0. T1: Tumor 20 mm or less in greatest dimension. T1 includes T1mi. T1mi: Tumor 1 mm or less in greatest dimension. N0: No regional lymph node metastasis. M0: No clinical or radiographic evidence of distant metastasis. M0 includes M0(i+); for bone cancer, stage IA is defined as follows: T1, N0, M0, G1, GX. T1: Tumor 8 cm or less in greatest dimension. N0: No regional lymph node metastasis. M0: No distant metastasis. G1: Well differentiated-low grade. GX: Grade cannot be assessed. (partially adapted from AJCC 8th ed.)