Introduction/Background The International Federation of Gynecology and Obstetrics (FIGO) recently revised the staging system for endometrial cancer (EC) from FIGO2008 to FIGO2023. This revision entails a more detailed classification, incorporating both clinical and molecular characteristics. This study aimed to assess the influence of the FIGO revision, excluding molecular information, on the clinical outcomes of patients undergoing primary surgical treatment for EC.

Methodology We collected clinico-pathological and survival data from consecutive patients treated at the University Medical Centre Maribor, Slovenia, between January 2015 and December 2019. Data cutoff for survivors was November 9, 2023. Relapse-free survival (RFS) and overall survival (OS) were calculated from the date of the initial histopathological diagnosis. Patients unfit for surgical treatment or receiving neoadjuvant treatment were excluded. Statistical analysis was conducted using SPSS for Mac, IBM, version 26.

Results The study assessed 194 patients undergoing primary surgical management. The median age at diagnosis was 67 years (range: 38 - 87 years). Recurrences occurred in 17.5% (n=34), with 16% (n=31) experiencing disease-specific deaths. When comparing FIGO2008 to FIGO2023 classification, upstaging occurred in 15.5% (25 out of 161) of patients initially diagnosed with early EC (Stage I and II) and in 3% (1 out of 33) of patients with advanced EC (Stage III - IV). Median RFS in early EC was 65 months (recurrence rate: 10%; n=17), and OS was 69 months (event rate: 9%; n=15). Patients upstaged in the early EC group had significantly lower RFS (p<0.016) but not OS (p>.090). Patients with a stage shift in early EC based on FIGO2023 staging received recommendations for systemic therapy (radiotherapy and/or chemotherapy) in 92% of cases (n=23) and only follow-up in 8% of cases (n=2).

Conclusion The FIGO2023 classification significantly impacts assesment of women with early EC, even in the absence of molecular characteristics and will improve patient specific disease management.

Disclosures N/A.