Prognostic significance of estrogen, progesterone and HER2 receptors' status conversion following neoadjuvant chemotherapy in patients with locally advanced breast cancer: Results from a tertiary Cancer Center in Saudi Arabia

Background The prognostic impact of neoadjuvant chemotherapy (NAC) on the receptor expression status in patients with locally advanced breast cancer (LABC) is still not fully understood. We aimed to evaluate the changes in hormone (estrogen and progesterone) receptor (HR) and human epidermal growth factor receptor 2 (HER2) status post-NAC and their correlation with survival. Methods Patients with LABC who have received NAC between 2008 and 2015 and have been followed up till December 2019 at the Oncology Center, King Saud University, KSA were analyzed retrospectively. biomarker analysis of ER, PR & HER2 were done using immunohistochemistry (IHC) and Fluorescent in situ hybridization. Results Ninety-one patients fulfilled the inclusion criteria. HR status changed in 21(23.1%) patients, with a significant difference between patients with stable receptors and those with any receptor conversion; p = 0.000. Five (5.5%) initially HER2 negative tumors became HER2 positive and 10 (11%) initially HER2 positive tumors became HER2 negative after NAC. The difference in HER2 expression level before and after NAC was not statistically significant (p = 0.302). Univariate analysis relating patients' characteristics and 10-years disease-free survival (DFS) showed only significant correlations with the expressions of ER, PR, and any receptor conversion, (ER and/or PR) p< 0.001, p< 0.001, and p = 0.001; respectively. In the univariate analysis, none of the clinicopathological features showed a significant correlation with the OS except for the molecular subtypes PConclusions Patients with LABC have significant changes in the ER and PR receptor status following NAC. Post-NAC expressions change of ER and PR (ER and/or PR) are correlated to DFS. Retesting of the hormone receptors should be considered after NAC in Saudi patients with LABC.