Stage I includes: T1, N0, M0. T1: Tumor confined to the vulva and/or perineum. Multifocal lesions should be designated as such. The largest lesion or the lesion with the greatest depth of invasion will be the target lesion identified to address the highest pT stage. Depth of invasion is defined as the measurement of the tumor from the epithelial-stromal junction of the adjacent most superficial dermal papilla to the deepest point of invasion. N0: No regional lymph node metastasis. M0: No distant metastasis. (AJCC 8th Ed.) [from NCI]