Non-endometrioid histologies (Serous, Clear Cell, Carcinosarcoma) are automatically considered high-grade and often behave like p53abn disease, necessitating aggressive adjuvant chemoradiation even at anatomically early stages.

The 2023 update places heavy emphasis on Lymphovascular Space Invasion (LVSI). Substantial LVSI (multiple vessels involved) upstages the disease from Stage IA to Stage IB in the absence of deep myometrial invasion.