Abstract P3-06-49: Prognostic impact of discordance in hormone receptor status after the neoadjuvant chemotherapy in primary breast cancer

Abstract

Background: Hormone receptor (Estrogen receptor (ER), Progesterone receptor (PgR)) is an important biological marker for predicting prognosis and making effective treatment decisions. Discordance in these biomarkers between the primary tumor and recurrent lesions is reported frequently. However, it is not well known whether these biomarkers are affected by neoadjuvant chemotherapy and their impacts on outcomes still remain to be elucidated. The aim of the present study is to evaluate the changes in HR status after neoadjuvant chemotherapy in patients with operable breast cancer and their relationship with response to treatment and prognosis. Patients and Methods: Of 162 patients with stage II/III breast cancer patients receiving neoadjuvant chemotherapy from January 2005 to September 2012 at Keio University Hospital, 140 patients with non-pCR were analyzed. Patients were treated with sequential anthracycline and taxane. ER and PgR were assessed in both CNB performed prior to neoadjuvant chemotherapy and surgical samples. HR status was assessed by immunohistochemistry (IHC). ER/PgR status was determined using the Allred score and defined as positive when score was 3 and more. HR status was considered positive in cases of ER and/or PgR positivity. Pathological response criteria were classified as grade 0, 1, 2, or 3: grade 0 includes almost no change in cancer cells; grade 1 includes slight or marked changes in less than two thirds of area; grade 2 includes marked changes in more than two thirds of area; grade3 includes necrosis or disappearance of all tumor cells. Results: ER, PgR and HR positive rates before neoadjuvant chemotherapy were 72.9%, 67.1% and 76.4%, respectively. Changes in ER, PgR and HR status between CNB and surgical samples were 12.1% (4.3% gain; 7.8% loss), 17.1% (2.1% gain; 15.0% loss) and 9.3% (2.9% gain; 6.4% loss), respectively. In ER-discordant group, grade 2 rate of pathological response was significantly higher than ER- concordant group (61.1% vs. 30%, p=0.033), whereas there were no significant differences of pathological response between discordant and concordant group in PgR status. In the disease free survival (DFS), there were no significant difference between concordance and discordance group for ER, PgR and HR (p=0.216, 0.859, 0.233) after a median follow-up of 40.4 months. But patients with a loss in ER and/or HR status had a trend to a shorter DFS compared with the concordant ER and/or HR-positive group (p=0.169 and 0.154) Conclusions: After neoadjuvant chemotherapy, discordance of biomarkers was seen in 5-20%. The pathological response was significantly associated with the change in ER status. A loss in ER and/or HR status may affect a prognosis of breast cancer after neoadjuvant chemotherapy, but still need further investigation. Citation Format: Toshiaki Kurihara, Hanako Ueno, Masaru Takemae, Aiko Nagayama, Maiko Takahashi, Tetsu Hayashida, Hiromitsu Jinno, Yuko Kitagawa. Prognostic impact of discordance in hormone receptor status after the neoadjuvant chemotherapy in primary breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-06-49.