Progesterone receptor negativity is an independent risk factor for relapse in patients with early stage endometrioid endometrial adenocarcinoma.

In endometrioid endometrial adenocarcinoma (EEA), the currently established prognostic factors in clinical guidelines are stage and grade. Many guidelines include lymphovascular invasion (LVI) and tumor size as prognostic factors. Although several studies have associated lack of estrogen (ER) and progesterone receptor (PR) expression with reduced outcome, the prognostic use of these markers is uncommon. Better prognostication of clinical behavior would be useful in patients with early stage (I-II) disease. In this study we evaluated ER and PR as prognostic factors in EEA, and compared their expression with other potential biomarkers and clinical parameters. Tissue microarrays were constructed from 182 patients with stages I-II EEA. ER, PR, p53, Ki-67, PTEN, MLH and HER-2 expression were assessed by immunohistochemical staining and HER-2 was confirmed with SISH. The results were correlated with clinicopathologic parameters and to disease-free survival. Eleven patients (6%) developed recurrent disease during a median follow up time of 62.8 months. In univariate analysis FIGO grade (p=0.019), positive expression of p53 (p=0.010) and negative PR expression (p=0.001) were associated with a shorter disease-free survival. In multivariate analysis only negative PR expression (p=0.019) was significantly associated with a shorter disease-free survival. LVI and tumor size where not of prognostic value. Lack of PR expression is a strong, independent risk factor for tumor recurrence in patients with stages I-II endometrioid endometrial cancer. The use of this easily measurable biomarker as a prognostic factor in the clinical context should be considered and tested in a larger patient population.