Introduction/Background The influence of molecular profiling on the pattern of recurrence of endometrial cancer (EC) has been scarcely studied. We aimed to analyze the pattern of first recurrence of patients with EC according to molecular classification, and to assess the independent role of molecular profiling on each type of failure.

Methodology Retrospective single-center study including patients diagnosed with EC stage I-IVB (FIGO 2009) between December 1994 and May 2022, who underwent primary surgical treatment and had a complete molecular profile. First recurrence was classified as isolated or multiple, and as vaginal, pelvic, peritoneal, nodal and distant.

Results We included 658 patients: 42.8% had non-specific molecular profile tumors (NSMP), 35.5% had mismatch-repair deficient tumors (MMR-d), 14.4% had p53-abnormal tumors (P53abn) and 7.1% had POLE-mutated tumors (POLE-mut). In total, 18.5% patients presented a recurrence: 65.6% were isolated and 34.4% multiple, with no differences regarding molecular subtype (p=0.924). P53abn tumors recurred mainly as distant (28.4%) and peritoneal (21.1%) disease, while patients with NSMP tumors presented predominantly with distant failures (10.3%), and MMR-d with locoregional recurrences (9.4%). Only one recurrence was diagnosed in the POLE-mut group, consisting of an isolated aortic relapse, treated locally and free of disease at the end of follow-up. On multivariate analysis, p53abn was the only independent risk factor for peritoneal failure (OR 8.54, 95%IC 2.0–36.34). Vaginal recurrence was independently associated with p53abn molecular profile (OR 6.51, 95%IC 1.13–37.41) and lymph vascular space invasion (LVSI). P53abn and NSMP were independent predictors for distant recurrence (OR 3.31, 95%IC 1.12–8.66 and OR 2.35, 95%IC 1.10–5.04, respectively), along with LVSI and high-grade tumors. Molecular profile was not independently associated to pelvic and nodal recurrences.

Conclusion EC featured different patterns of recurrence depending on molecular profile. P53abn molecular profiling was the only independent risk factor for peritoneal relapse, while NSMP showed a strong association with distant failures.

Disclosures No disclosures.