Prognostic significance of biomarker discordance in breast cancer patients with neoadjuvant chemotherapy

Abstract

San Antonio Breast Cancer Symposium 2016). The model with 4 factors, including the histologic type (invasive ductal or lobular), the expression level of PgR (Allred score 7,8 or < 6) and Ki67 (< 24 or > 24), and the presence of lymphovascular invasion, showed that 92% of patients with high PgR positive and Ki67 < 24 could be classified as low-RS with an AUC of 0.843 (95%CI: 0.790-0.896). The aim of this study was to validate our prediction model with external patient data. Methods: A validation set of clinicopathological data from 77 patients who had primary invasive carcinoma surgically resected and underwent OncotypeDxV R was obtained from Showa University, school of medicine, Tokyo, Japan. Results: According to the distribution of 4 factors between two cohorts, there was a significant difference in Ki67 level (<0.01) but not in histologic type, the expression level of PgR, and lymphovascular invasion. The prediction model of the validation cohort had still high enough discriminatory ability having an AUC of 0.705 (95%CI: 0.584-0.827). Conclusions: Regardless of the inconsistency of Ki67 level between institutes, our model could provide useful information to predict low-RS in hormone receptor-positive invasive breast cancer patients. This model would be helpful to select patients who had better apply OncotypeDXV R . Legal entity responsible for the study: Yasue Tsuchida Funding: None Disclosure: All authors have declared no conflicts of interest.