Differences in Breast Cancer Survival by Molecular Subtypes in a Single Treating Centre

Introduction: Breast cancer is divided into various molecular subtypes including luminal, HER2 and basal type. This study aims to determine survival by molecular subtype of pre- and post-menopausal patients with breast cancer. Method: This retrospective study included 1234 patients diagnosed with invasive breast cancer between years 2011 until 2015. Subtypes of breast cancer were categorized into 4 groups; Luminal A, Luminal B, HER2-overexpressed and Triple Negative Breast Cancer (TNBC). The impact of overall survival (OS) was assessed by Kaplan-Meier survival curves and significance was assessed using the log-rank test. A p-value <0.05 was considered statistically significant. Results: Total 1234 breast cancer women were included in this study. Median age among premenopausal and postmenopausal women were 44 and 59 years respectively. Total of 799 patients (64.7%) were still alive after a mean follow-up of 7.4 years (95% CI: 7.2-7.6). Higher OS was found in Luminal A both in premenopausal and in postmenopausal patients (76.8% and 64.2%).  Lowest OS was found in both premenopausal and postmenopausal HER2-overexpressed patients (52.8% and 51.2%).  Conclusion: HER2-overexpressed breast cancer is associated with lowest survival in both preand postmenopausal women with breast cancer.