Stage IA includes: T1a, N0, M0. T1a: Tumor measuring less than 0.8 mm in thickness. Ulceration status: Without ulceration. N0: No regional lymph node metastasis detected. Presence of in-transit, satellite, and/or microsatellite metastases: No. M0: No evidence of distant metastasis. LDH level is not applicable. (AJCC 8th ed.) [from NCI]