The criteria for microinvasive endometrial cancer are considered to be myometrial invasion depth that does not depend on the thickness of the uterine wall and tumor histological differentiation and that is less than 5 mm; and the minimal rate of regional lymph node metastasis. In case of early invasive cancer, it is necessary to distinguish two phases of a malignant process: 1) a phase of stromal invasion and 2) a phase of early myometrial invasion (not more than 5-mm myometrial infiltration). In microinvasive cancer, one may refuse extended surgery and radiotherapy as a step of combination treatment, without worsening its long-term results. Simple extirpation of the uterus and appendages may be a sufficient and adequate therapy option for these forms of endometrial cancer.