Prognostic Significance of HER2 Expression Changes Following Neoadjuvant Chemotherapy in Saudi Patients With Locally Advanced Breast Cancer

Abstract

BackgroundProgesterone receptor (PR), estrogen receptor (ER), and human epidermal growth factor receptor 2 (HER2) significantly influence disease prognosis and therapeutic response in patients with breast cancer. Neoadjuvant chemotherapy (NACT) can change the receptor status, affecting the disease characteristics. Patients and MethodsA retrospective chart review was carried out at a single tertiary care hospital in Riyadh, Kingdom of Saudi Arabia, from December 2008 to December 2014, where 91 adult female patients diagnosed with locally advanced breast cancer planning to receive NACT were included. Original pathology and surgical histopathology reports were assessed, and patients were followed up to recurrence, death, or until December 2019. An expression for the ER, PR, and HER2 was carried out in pre and post NACT specimens by an experienced pathologist, and all HER2 with 2+ immunohistochemistry was sent for fluorescence in situ hybridization as per American Society of Clinical Oncology guidelines. ResultsER pre- and postoperatively changed from positive to negative in 17.6% of patients and from negative to positive in 1.1% of patients (P < .001). ER status remained stable in 81.3% of patients. PR changed from positive to negative in 13.2% of patients, and from negative to positive in 3.3% of patients (P < .001), whereas it remained stable in 83.5% of patients. HER2 changed from positive to negative in 11% of patients, and from negative to positive in 5.5% of patients (P < .001), and it remained stable in 83.5% of patients. No significant association was found between overall survival and disease-free-survival with HER2 expression change. ConclusionNACT can induce changes in the ER, PR, and HER2 status, which should be evaluated post-NACT to choose the optimal treatment regimens.