Impact of the FIGO 2023 Staging System on the Adjuvant Treatment of Endometrial Cancer: A Comparative Analysis with FIGO 2009

Background: ProMisE (Proactive Molecular Risk Classifier for Endometrial Cancer) has brought about the publication of the FIGO 2023 staging system with a significant impact in practice for endometrial cancer (EC). Methods: In this comparative study, we investigated the need for adjuvant treatment according to FIGO 2023, for each FIGO 2009 stage. We prospectively enrolled EC patients from June 2021 to June 2024, collected classical risk factors and classified according to FIGO 2009. Afterwards, we reclassified the same women according to FIGO 2023 and grouped them according to ESMO/ESTRO/ESGO risk factors. Results: We collected 211 eligible patients. We found 176 patients with FIGO 2009 I–II and 35 women with FIGO 2009 III–IV. Based on classic anatomopathological risk factors and FIGO 2009, adjuvant treatment was indicated in 124 (70.5%) patients with FIGO 2009 I–II (vaginal brachytherapy = 48; external beam radiotherapy with or without vaginal brachytherapy = 63; chemotherapy with external beam radiotherapy with or without vaginal brachytherapy = 13) and in 35 (100%) women with FIGO 2009 III–IV (all underwent chemotherapy). After FIGO 2023 re-staging, the women with early-stage EC, were more frequently candidates for no treatment, with a decreased relative risk (RR) for adjuvant treatment (RR 0.84; CI95% 0.74–0.95; p < 0.01) when compared to the previous FIGO classification. No significant risk (RR 1.01; CI95% 0.76–1.3; p = 0.08) for a more aggressive adjuvant treatment was noted after FIGO 2023 re-staging. In FIGO stage III–IV, no changes in the treatment modalities were observed. Conclusions: The re-staging according to FIGO 2023 of women previously staged to FIGO 2009 I–II, yields an RR of 0.84 to spare any type of adjuvant treatment.