The prognostic significance of estrogen and progesterone receptors in grade I and II endometrioid endometrial adenocarcinoma: hormone receptors in risk stratification.

Objectives: Although patients with grade I and II endometrioid endometrial adenocarcinoma (EEA) are considered with good prognosis, among them 15%-25% died in 5 years. It is still unknown whether integrating estrogen receptor (ER) and progesterone receptor (PR) into clinical risk stratification can help select high-risk patients with grade I-II EEA. This study was to investigate the prognostic value of ER and PR double negativity (ER/PR loss) in grade I-II EEA, and the association between ER/PR loss and The Cancer Genome Atlas (TCGA) classification.

Methods: ER and PR were assessed by immunohistochemistry on hysterectomy specimens of 903 patients with grade I-II EEA. ER and PR negativity were determined when <1% tumor nuclei were stained. Gene expression data were obtained from the TCGA research network.

Results: Compared with ER or PR positive patients (n=868), patients with ER/PR loss (n=35) had deeper myometrial infiltration (p=0.012), severer FIGO stage (p=0.004), and higher rate of pelvic lymph node metastasis (p=0.020). In univariate analysis, ER/PR loss correlated with a shorter progression-free survival (PFS; hazard ratio [HR]=5.25; 95% confidence interval [CI]=2.21-12.52) and overall survival (OS; HR=7.59; 95% CI=2.55-22.60). In multivariate analysis, ER/PR loss independently predicted poor PFS (HR=3.77; 95% CI=1.60-10.14) and OS (HR=5.56; 95% CI=1.37-22.55) for all patients, and poor PFS for patients in stage IA (n=695; HR=5.54; 95% CI=1.28-23.89) and stage II-IV (n=129; HR=5.77; 95% CI=1.57-21.27). No association was found between ER/PR loss and TCGA classification.

Conclusion: Integrating ER/PR evaluation into clinical risk stratification may improve prognosis for grade I-II EEA patients.