Endometrial cancer (EC) is the most common gynecological cancer worldwide [1]. In South Korea, EC surpassed other gynecologic cancers to have the highest annual incidence rate in 2019, a trend that has persisted [2]. This increase has been observed in women younger than 45 years [3,4], with a rising number of patients desiring pregnancy or fertility preservation.

The primary treatment for EC involves surgery, typically hysterectomy and/or bilateral salpingo-oophorectomy [5]. However, fertility preservation procedures are performed in a subset of women with early–stage EC who wish to conceive. Complete response (CR) is achieved in approximately 80 % of patients with hormonal fertility-sparing treatment (FST), with pregnancy and live birth rates ranging from 25.8 to 80.8 %, though recurrence rates range from 24.6 to 40.9 % [[6], [7], [8], [9], [10], [11], [12]]. European Society of Gynecological Oncology (ESGO) guidelines recommend completion hysterectomy for patients who have completed childbearing after the FST; however, the evidence quality is moderate (level of evidence II-IV, Grade A-B) [5,13]. Some patients opt to preserve fertility after completing pregnancy, yet oncologic outcomes of completion hysterectomy in these cases have not been reported. This study evaluated oncological outcomes of completion hysterectomy versus no completion hysterectomy in patients who achieved CR and completed childbearing after the FST.