Introduction/Background Molecular profiling classification in endometrial cancer has been introduced into clinical practice by the ESGO/ESMO/ESP recommendations in 2021 and then into the FIGO staging system in 2023. If the molecular assessment reveals p53abn, the cancer is upstaged, while if it shows POLEmut, it is downstaged, changing indications to adjuvant treatment.

The primary purpose of this study was to compare the indications for adjuvant treatment in endometrial cancer patients based on their histopathological features and FIGO staging (2018) with or without the molecular profile assessment.

Methodology Among 125 patients treated surgically for endometrial cancer, we retrospectively assessed the molecular profiling with NGS of p53abn and POLEmut and compared their criteria for receiving adjuvant treatment.

Results POLEmut was detected in 5 patients (4.0%), while p53abn in 15 patients (12.0%). Double classifiers (both positive p53abn and POLEmut) (5 patients, 4.0%) were added to the POLEmut group.

POLEmut group, according to FIGO 2018 staging, were found in stage IA (60.0%, n=6), IB (30.0%, n=3), and II (10.0%, n=1), while p53abn group were found in IA (40.0%, n=6), IB (20.0%, n=3), II (13.3 %, n=2), IIIC1 (20.0%, n=3) and IVA (6.7 %, n=1). 60.0% (n=6.0) of POLEmut cases were classified as low-grade cancers (endometroid G1/G2) and 40.0% (n=4) as aggressive (endometroid G3 and other nonendometroid types). In the p53abn profile group, 20.0% of patients (n=3) were described as low-grade. LVSI was noted in 40.0% of POLEmut group cases and 46.7% of p53abn cases (n=7).

Seven women in the POLEmut group were referred to adjuvant treatment, showing overtreatment rate of 70.0%. In contrast, two patients in the p53abn group were not assigned for adjuvant treatment (both low-grade FIGO IA, LVSI negative), bringing undertreatment rate of 13.3%.

Conclusion These results highlight the importance of molecular profiling as a part of qualifying patients for the most beneficial adjuvant treatment.

Disclosures No conflict of interests.