Effect of estrogen and progesterone receptor expression on progression-free and overall survival outcomes in low-grade serous ovarian cancer.

person Marta Llaurado Fernandez University of British Columbia, Vancouver, BC, Canada info_outline Marta Llaurado Fernandez, Amy Dawson, Hannah Kim, Nicole Lam, Maegan Bruce, Holly Russell, Joshua Hoenisch, Diane M. Provencher, Melica Nourmoussavi, Cyril Blake Gilks, Cheng-Han Lee, Martin Kobel, Nelson Wong, Stephanie Scott, Gabriel Dimattia, Anne-Marie Mes-Masson, Mark Stafford Carey

Authors person Marta Llaurado Fernandez University of British Columbia, Vancouver, BC, Canada info_outline Marta Llaurado Fernandez, Amy Dawson, Hannah Kim, Nicole Lam, Maegan Bruce, Holly Russell, Joshua Hoenisch, Diane M. Provencher, Melica Nourmoussavi, Cyril Blake Gilks, Cheng-Han Lee, Martin Kobel, Nelson Wong, Stephanie Scott, Gabriel Dimattia, Anne-Marie Mes-Masson, Mark Stafford Carey Organizations University of British Columbia, Vancouver, BC, Canada, University of Montreal, Montreal, QC, Canada, Vancouver General Hospital, Division of Anatomical Pathology, Vancouver, BC, Canada, BC Cancer, Vancouver and University of British Columbia, Vancouver, BC, Canada, University of Calgary, Calgary, AB, Canada, BC Cancer Research Centre, Vancouver, BC, Canada, Dalhousie University, Halifax, NS, Canada, University of Western Ontario, London, ON, Canada, Centre Hospitalier de l‘Université de Montréal/CRCHUM, Montreal, QC, Canada, Obstetrics and Gynecology, University of British Columbia, Vancouver, BC, Canada Abstract Disclosures Research Funding Other Foundation Background: Research on ER/PR receptor function in low-grade serous ovarian cancer (LGSC) and the determinants of response to treatment are lacking. A recent study (Sehouli et al.,2018) described ER/PR immunohistochemistry (IHC) cut-points that distinguished PFS. Thus, we report on a group of patients with ER/PR expression by IHC in tumor samples of patients with LGSC and used this information to evaluate survival outcomes. Methods: Clinical information and FFPE sections were obtained from the Canadian Ovarian Experimental Unified Resource (COEUR). Tissue microarray (TMA) sections were stained for ER/PR using standard IHC techniques (MK). 50 stage 3 and 5 stage 4 patients were analyzed. ER/PR expression was scored using a simple scoring system ( < 1% cells staining, 1-50%, and ≥ 50%) and Allred scoring. We compared Kaplan-Meier (KM) survival (PFS and OS) curves using Log rank testing and Cox regression was used to model predictive/prognostic factors. A p-value of 0.05 was considered significant. Results: The mean age of the population was 49.5 years (SD;13.7). Ninety percent of patients were treated by surgery followed by platinum-based chemotherapy (PBC). Simple scoring did not discriminate outcomes as well for ER levels. PR Allred score ( < 2, vs 2- < 6 vs ≥6) clearly discriminated KM curves for PFS (p = 0.036) and OS (p = 0.01). For Allred ER score ( < 7 vs.7- < 8 vs 8) did not distinguish PFS (p = 0.4) but notably most patients received PBC after surgery. ER Allred score significantly distinguished OS (p = 0.008). Significant factors on Cox regression for PFS were residuum (p = 0.008;95%CI:1.2-3.1) and PR (p = 0.05;95%CI:0.39-0.99), whereas for OS ER(p = 0.01:95%CI:0.2-0.8) and residuum (p = 0.04;95%CI:1-2.8). Conclusions: ER/PR expression by Allred scoring was associated with PFS and OS. Patients will benefit from much needed research on ER/PR prediction/prognosis in LGSC. This work can inform clinical trials selection/stratification and patient selection for endocrine treatment.