Prognostic significance of immunohistochemical markers in endometrial cancer treated with chemotherapy

Abstract

e16551 Background: The proportion of patients receiving chemotherapy for endometrial cancer is increasing both in the adjuvant and advanced setting. The literature describes many prognostic immunohistochemical factors in early stage endometrial cancer, the majority of whom will not receive chemotherapy. The aim of this study was to describe the biomarker expression for endometrial tumours treated with chemotherapy and to assess what constitutes a favourable and unfavourable profile for this patient group. Methods: For a subset of patients with either endometrioid, serous or a mixed mullerian morphology treated with chemotherapy at our centre between 1996 and 2008 an immunohistochemical profile of 14 biomarkers was studied (ERα, Erβ1, Erβ2, PR, PRB, P53, Rb, E-cad, MDM2, MIB-1, E2F1, p16, p13, and p21). A univariate analysis using cox regression of potential prognostic factors was then carried out. Results: In total 199 patients received chemotherapy for endometrial cancer over the 12 year period studied. Two year survival from commencement of chemotherapy for patients receiving adjuvant treatment was 45.2% and palliative treatment 28.1%. The commonest histological subtypes were endometrioid adenocarcinoma (40%), serous carcinoma (24.1%) and mixed mullerian tumours (14.6%). For the subset of 35 patients 38.2% of patients had positive immunohistochemical staining for ERα, 53% for PR, 73.5% for p16, and 94% for E2F1. Good prognosis was predicted by the strength of staining for E2F1 (HR 0.757, CI 0.216/0.902, p = 0.025) and poor prognosis by p16 (HR 1.470, CI 1.040/2.077, p = 0.029). Conclusions: Positive staining for ERα and PR was of similar frequency to previous studies of early stage endometrial cancer and did not significantly influence prognosis. Good prognosis correlated with E2F1 expression and poor prognosis with p16. A greater proportion of patients had serous morphology compared to published series of early stage endometrial cancer. Further study of prognostic factors in larger numbers of patients and built into prospective randomised trials may allow the creation of a prognostic model and guide the development of future clinical trials of targeted therapy. No significant financial relationships to disclose.