Objective Understanding ovarian involvement incidence and risk factors in women with endometrial cancer may inform the decision of ovary preservation.

Methods Our retrospective study included all consecutive fully surgically staged patients with endometrial cancer who underwent primary surgery between January 2005 and November 2021, assessing the incidence of ovarian metastasis, its role as a prognostic factor for recurrence and death, and evaluated predictors of adnexal involvement.

Results Women with International Federation of Gynecology and Obstetrics (FIGO) 2009 IIIA endometrial cancer comprised 2.3% of the population (36 of 1535 included patients), 23 (63.9%) with endometrioid histology, and a median age of 57.0 years (range 47.7–66.7). A higher body mass index, post-menopausal status, endometrioid histotype, and β-catenin expression were associated with a lower risk of adnexal involvement. Conversely, dMMR phenotype, p53 expression, myometrial infiltration >50%, lymphovascular space invasion, and cervical stromal invasion were independent predictors of an increased risk of adnexal involvement. A total of 145 (9.5%) patients had adnexal involvement, with an incidence rate of 0.27/100 person-days. Overall survival for FIGO (2009) stage IIIA was 88.9%.

Conclusions Our study showed that ovarian preservation may be considered for younger patients with low-risk endometrial cancer (G1 and G2 tumors, absence of lymphovascular space invasion, no cervical involvement, and myometrial invasion <50%), adding a favorable predictive role to higher body mass index and high β-catenin expression.