Correlation of hormonal receptor level and survival outcome in HER2-positive nonmetastatic breast cancer.

Abstract

e12568 Background: In human epidermal growth factor 2 (HER2)-positive breast cancer, emerging evidences imply that clinical behavior and prognosis differ according to hormone receptor (HR) status. However, there is no conclusion about the relevance between estrogen receptor (ER) or progesterone receptor (PR) expression and clinical outcome of HER2-positive breast cancer. Our study is designed to determine the effect of different ER/PR levels on survival benefit of HER2-positive early breast cancer. Methods: 984 non-metastatic HER2-positive breast cancer patients between January 2009 and December 2016 were retrospectively reviewed and HR+/HER2+ patients were further classified into several subgroups based on ER expression level (Low/L: 1-9%; Median/M: 10-74%; High/H: 75-100%) and PR expression level (Low/L: 0-19%; High/H: 20%-100%). Clinical features and survival outcomes were evaluated. Results: A total of 461 HR+/HER2+ and 523 HR-/HER2+ breast cancer patients were included in our study and 69.8% of them received target therapy (HR+ 67.5%, HR- 71.9%). While HR+/HER2+ breast cancer showed better survival than HR-/HER2+ subtype in 5-year disease free survival (DFS, 92.6% vs 87.6%, p = 0.002), no significant difference was observed between 5-year DFS rates in ER+/PR+ and ER+/PR- subgroup (94.3% vs 89.7%, p = 0.150). However, a possible correlation was found between ER/PR levels and DFS both in HR+/HER2+ (p = 0.057) and all HER2+ (p < 0.001) breast cancer. In HR+/HER2+ breast cancer, all subgroups showed DFS improvement trend versus M-ER/L-PR patients and hazard ratio of H-ER/H-PR subtype had a statistical difference (0.36, 95%CI 0.13-0.99, p = 0.047). In all HER2+ patients, hazard ratio of H-ER/H-PR compared with HR- subtype was 0.32 (95% CI, 0.13-0.80, p = 0.015). M-ER/L-PR presented similar DFS outcome with HR- subtype in our study. Conclusions: ER/PR expression may become a predictor of survival benefit in HER2-positive non-metastatic breast cancer and a higher ER/PR expression level might be associated with better DFS.