Introduction Aberrant beta-catenin distribution has been theorized as a predictive biomarker for recurrence in early stage, low grade endometrioid endometrial cancer.

Methods Retrospective single institution cohort study of 298 endometrioid endometrial cancer patients 5/2018–2/2022. Demographic and tumor molecular characteristics collected. Beta-catenin status defined as aberrant nuclear distribution, wild-type plasma membrane distribution. X² test, Fisher test, adjusted multivariable logistic regressions, sensitivity analyses were performed.

Results Most tumors were stage IA (55.4%) grade 1 (65.8%). 45.3% of tumors aberrant beta-catenin, 70% MMR proficient, 94% p53 wild type, 95% POLE wild type, 98% ER positive, 97.3% PR positive. Aberrant beta-catenin distribution in 74.1% of FIGO grade 1 tumors, 22.5% of LVSI tumors and in 69% of patients younger than 70 years. Aberrant status in 39.6% of recurrences vs. 46.4% without recurrence (p=0.38). Recurrences in the vagina (29.2%), lung (25%). In early stage, low grade cohort, recurrence did not vary by beta-catenin status (42.9% of aberrant with recurrence versus 47.2% of aberrant without recurrence (p=0.71). In the NSMP cohort, recurrence did not vary by beta-catenin status (61.9% recurred vs. 53.2% did not recurred) (p=0.45). In adjusted logistic regression, aberrant beta-catenin distribution did not affect disease recurrence in the overall cohort with aOR 1.12 [95% CI 0.50–2.48], early stage/low grade cohort with aOR 1.03 [0.35–3.10], and the NSMP cohort with aOR 0.58 [0.14–2.56]. Among tumors that received adjuvant RT (n=84), 2.86% aberrant beta-catenin tumors recurred vs. 8.16% wild-type beta-catenin recurred.

Conclusion/Implications Aberrant beta-catenin distribution did not significantly correlate with recurrence in early stage, low grade endometrioid uterine cancer