178 Complex atypical hyperplasia: a study of risk factors associated with concurrent endometrial cancer

Introduction/Background To identify the clinical/imaging factors associated with a higher risk of a diagnosis of malignancy in the final HPE report, in patients with preoperative biopsy diagnosis of CAH, and the SLN positivity in this cohort. Methodology A retrospective single institution cross sectional and comparative study of patients with a preoperative biopsy diagnosis of CAH, who underwent staging surgery with SLNB from March 2015 to June 2023.Pearson Chi Square and Pearson Chi Square with continuity was used to find association between two categorical variables and 95% confidence intervals(CI). Results Out of 54 patients with a preoperative diagnosis of CAH,26 (48.14%) had CAH, and 28 (51.85%) had invasive cancer on final pathology. Diabetes mellitus (p=0.05) & a history of heavy menstrual bleeding were found to be significantly associated with concurrent EC(p=0.017).The median preoperative endometrial thickness was significantly greater in the EC group, i.e. 13 mm (range 6–28 mm) than in the CAH group -9 mm (range 5–35 mm; p=0.004). Preoperative MRI finding of >50% myometrial invasion was significantly associated with upgradation to EC (p=0.03).Patient in whom preoperative biopsy was done in a tertiary care oncology centre like ours, had a lower risk of biopsy upgrade when compared to biopsy performed in smaller peripheral centres ( p-0.002). Of those with concurrent EC, 27 were type I endometrioid & Only 1 patient had type 2 EC .19 patients were stage IA,7- 1B,1–3A and 1–3C1.Only 1 patient (0.85%)of all had SLN metastasis. Conclusion HMB,DM,ET ≥13 mm,preoperative imaging showing >50% MI, and EB done in a non oncology/peripheral centre were significant preoperative factors in identifying patients at higher risk for concurrent EC.SLN positivity rate is very low in this cohort, owing likely to the fact that most of these were low grade, early stage cancers. Disclosures None.