The prevalence of ER-low-positive breast cancer and its relation to tumor characteristics in Syria

Background: Breast cancer is a heterogeneous disease with varying clinical behaviors and responses to endocrine therapy. In particular, estrogen receptor (ER)-positive breast cancer can present with various subtypes, and the effectiveness of anti-hormone therapy on ER-low-positive tumors is unclear. This study aimed to evaluate and characterize ER-positive subtypes in patients admitted to the Surgical Oncology Clinic in the National Hospital of Jableh in Syria between 2020 and 2022. Patients and Methods: This study included 120 patients diagnosed with breast cancer; the data from each patient’s report were collected to classify them according to grade, stage, LNR, tumor size, and nodal stage. Results: The prevalence of ER-low-positive subtype was 23.33%. There was a significant difference between ER-negative and ER-positive subtypes concerning age, grade, stage, and LNR. Additionally, we confirmed a variation between ER-low-positive and ER-high-positive tumors, which may explain the difference in therapeutic response in ER-positive tumor patients taking anti-ER drugs. Conclusion: Further research is necessary to study the association between therapeutic response and ER-staining intensity breast cancer subtypes.