Introduction/Background It is well established that around one-third of patients with atypical Endometrial hyperplasia (AEH) develop endometrial cancer (EC). The aim of the study is to determine the incidence of EC in AEH patients in UHL and to explore the reasons why AEH patients opted for conservative management.

Methodology A retrospective cohort study including 119 patients recruited from the University Hospitals of Leicester from 01/01/2015 to 01/01/2020 with a diagnosis of AEH by pipelle or endometrial biopsy. Patients were divided into two groups according to the management modality: primary surgery (n=99) and conservative treatment (n=20).

Results EC was diagnosed in 34.4% of patients with AEH managed by primary surgery. Moreover, the incidence of EC in patients with AEH managed conservatively is 25%. The main reason for opting for conservative management was that patients were unfit for surgery when assessed in the high-risk Anaesthetic Clinic (35%).

Conclusion _{Total hysterectomy is the safest first line of treatment in AEH due to the high risk of concurrent EC and progression to EC. Currently, there is no reliable follow up intervention to distinguish between concurrent EC and progression of AEH. Adequate discussion and counselling are essential when discussing conservative management for women with atypical complex endometrial hyperplasia. Moreover, counselling patients regarding high risk of developing concurrent endometrial cancer and/or progression to endometrial cancer should be done.}