J. White1, M. Gutman2, D. Dietrich3, C. H. Son1, and Y. Hasan2; 1Department of Radiation and Cellular Oncology, University of Chicago Medical Center, Chicago, IL, 2Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL, 3University of Chicago Medical School, Chicago, IL
Purpose/Objective(s): The new FIGO 2023 staging for endometrial cancer intends to improve concordance of clinical outcomes with pathological features. The goal of this study is to report outcomes with the new FIGO 2023 staging system and assess stage migration. The study hypothesis is stage migration will provide more accurate prognostication for disease free survival (DFS). Materials/
Methods: An IRB approved retrospective review was performed in patients (FIGO 2009: FIGO 1A-4B/ FIGO 2023: Stage 1A-4C) treated definitively for endometrial cancer with hysterectomy followed by radiation therapy +/-chemotherapy at a single institution. Patients who could not be fully staged were excluded. Extent of LVSI was not available for 10 patients. Patients were staged based on both FIGO 2009 and FIGO 2023 staging systems. Stage migration was defined as, if a change in stage number occurred (example: stage 1A to 2C was considered stage migration, while stage 1A to 1C was not). The Kaplan–Meier method estimated DFS. Results: From 2012-2021, 111 patients received EBRT alone 27.0% (n=30), vaginal cuff brachytherapy alone 34.2% (n=38), or both 38.7% (n=43). Mean age at diagnosis was 66.5 (range: 30.4-87.6). Median follow up was 61.5 months from radiation (range: 0.5-188 months). 66.6% (n=74) of patients had a high-risk histology: grade 3 or undifferentiated endometrioid adenocarcinoma (n=27), serous (n=22), clear cell (n=6), carcinosarcoma (n=18), or high grade neuroendocrine (n=1). FIGO 2009 staging results: 1A(n=34), 1B (n=18), 2 (n=12), 3A (n=10), 3B (n=2), 3C1 (n=16), 3C2 (n=12), 4A (n=1), 4B (n=6). Restaging based on the FIGO 2023 classification system: 1A2( n=7), 1A3 (n=1), 1B (n=12), 1C (n=8), 2A (n=6), 2C (n=31), 3A1 (n=1), 3A2 (n=7), 3B1 (n=2), 3B2 (n=1), 3C1 (n=16), 3C2 (n=12), 4A (n=1), 4B (n=3), 4C (n=3). In patients initially staged 1A or 1B (n=52), stage migration to 2C occurred in 48.1 % (n= 25) of patients. Stage migration occurred in 23.4% (n=26) of patients and primarily occurred from stage 1A/1B to 2C. Based on the 2009 FIGO staging system, 2-yr DFS was 80.4%, 58.3%, 72.4%, and 28.6% for stages 1,2,3, and 4, respectively. Based on the 2023 FIGO staging system, 2-yr DFS was 85.3%, 69.9%, 71.7%, and 28.6% for stages 1,2,3, and 4, respectively. No significant difference in recurrence rates between patients originally staged in 2009 as FIGO stage 1A/1B and migrated to FIGO stage 2C under the 2023 staging system compared to patients that were originally staged FIGO stage 1A/1B in 2009 and did not have stage migration (Recurrence rates: 36% vs. 18.5%, p=0.215). Conclusion: A significant proportion of 2009 FIGO IA-B patients had stage migration to 2023 FIGO II. The 2023 classification showed trend to higher DFS for Stage I-II patients and greater ability to prognosticate disease outcomes. Further study is needed when recommending adjuvant therapy in the context of prior studies using the 2009 staging system.
