ESTRO 2024 - Abstract Book

S978

Clinical - Gynaecology

ESTRO 2024

Results:

There were 153 women diagnosed with non-MMRd EC at a median age of 62 (IQR 54–71) and followed for a median of 31 months (IQR 20–57). POLEmut patients who received any adjuvant RT were considered over-treated (37% [10 of 27]); p53abn patients who did not receive pelvic EBRT were considered under-treated (90% [26 of 29]); and NSMP patients who received pelvic EBRT were considered over-treated (6% [6 of 97]) while those who received no adjuvant RT were considered under-treated (72% [70 of 97]) (Table 1). Across the entire cohort, 96 patients (63%) were under-treated and 16 (10%) were over-treated. Patients who did not receive any adjuvant RT for p53abn EC, the least favorable molecular class (Figure 2) with the greatest locoregional benefit from RT, accounted for 20 of the 96 under-treated patients (21%). Under-treatment was associated with stage IA and low-grade disease, whereas over-treatment was associated with high-grade disease (Table 1, P<0.05). The distribution of EC molecular classes also differed by race. Of the 253 samples, 70% (177) were from White patients, 16% (41) were from Black patients and 5% (13) were from Asian patients. EC classified as p53abn was more common among Black patients (22%) than White (vs. 9%, P=0.02) or Asian patients (vs. 0%, P=0.06).

Figure 2. Kaplan-Meier plot of progression-free survival for different molecular classes of stage I endometrioid EC in TCGA.