OP17.01: Liquid biopsy can assist preoperative imaging in staging of women with endometrial cancer

Standard preoperative diagnostics in endometrial cancer (EC) typically relies on clinical imaging features and pathohistological characteristics to facilitate staging for clinical decision-making. Recent advancements introduced liquid biopsy as a promising tool for leveraging cell-free DNA (cfDNA) to potentially enhance the precision of assessing EC behaviour, thereby contributing to preoperative staging. We aimed to assess the utility of preoperative cfDNA analysis in assisting clinical staging of EC. This prospective study was conducted at a university hospital and enrolled 115 women undergoing primary EC treatment between January 2020 to August 2023. All patients underwent transvaginal ultrasound (TVUS) examination, molecular tumour characterisation and determination of cfDNA quantities from peripheral venous blood samples. cfDNA was extracted from 1mL of plasma using ccfDNA/RNA Kit and diluted in 20 uL of distilled H2O. cfDNA concentration was determined through the use of the High Sensitivity DNA Chip/2100 Bioanalyser, Agilent and was represented in ng/mL plasma. The median age of women in this study was 68 years (min 41.0 - max 87.0 years), with a median BMI of 31.0 (min 17.0 - 44.0). Significant differences in cfDNA quantities between different molecular groups (p < .029) with POLEmut patients showing highest levels of available cfDNA in POLEmut patients (mean rank 67.6 ng/ml plasma) and lowest levels in p53abn EC (mean rank 42.77 ng/ml plasma). cfDNA was independent of tumour stage (p > .370) and the need for adjuvant treatment (either radiotherapy or chemotherapy and radiotherapy) (p > .090). A positive correlation was found between cfDNA concentration and ultrasound assessed myometrial invasion (%) (rs = 0.295; p < .020). The advancements in molecular tumour characterisation in EC necessitate a shift towards personalised therapy planning. Incorporating cfDNA analysis alongside expert TVUS for pretreatment staging offers the potential for more comprehensive tumour assessment and facilitates tailored management strategies in EC.