Article Text
Abstract
Introduction/Background Recently, the prognostic role of estrogen receptor (ER) expression has received increasing attention in endometrial cancer (EC) molecular classification. Unlike breast cancer, according to the current knowledge, there is no agreement about the cut-off to evaluate ER negativity in EC. Recent evidence support the cut-off of <=1% while others showed that the cut-off of <10% can identify the group with worse survival outcomes. This study aims to assess the prognostic value of the two proposed ER cut-offs in EC molecular classification
Methodology All presumed uterine-confined ECs undergoing surgical staging at Fondazione Policlinico Universitario A. Gemelli were retrospectively included. Applying an immunohistochemistry (IHC)-based model, patients were stratified into: MMR-proficient and p53 wild-type (MMRp), mismatch repair deficient and p53 wild-type (MMRd), and p53-abnormal (p53abn) EC. Similarly, ER expression was assessed by IHC, defining three sub-classes: <=1%, 2–10% and >10%. ER expression was matched with different molecular classes.
Results 1309 ECs were included. Age, BMI, histology, and adjuvant treatment differed between the three cohorts (p<0.05). As expected, the distribution of ER expression was different between MMRp, MMRd and p53abn EC patients. The Kaplan-Meier survival curves for disease-free survival demonstrated similar outcomes between ER <=1% and 2–10% cohorts, different from ER >10% cohort in MMRs EC patients (p<0.001). Interestingly, these data were also confirmed in the high-risk p53abn EC cohort, in which ER<10% appears to be again a reliable cut-off influencing survival outcomes (p=0.025).
Conclusion In this large retrospective EC series, we demonstrated that ER expression <10% significantly impacted disease-free survival in different molecular classes and no significant differences between ER <=1%, and 2–10% cohorts were shown. These results may lay basis to recognize ER <10% as an adequate cut-off to properly evaluate the clinical impact of ER expression negativity in EC molecular classification. Longer follow-up and prospective studies are necessary
Disclosures None.