Clinicopathological Factors Determining the Pathological Response to Neoadjuvant Therapy in HER2 Positive Breast Cancer

Abstract

Aim: In our study, we aimed to determine the clinicopathological factors affecting the pathological response after neoadjuvant chemotherapy inHER2 positive breast cancer.Materials and Methods: A total of 54 HER2 expression positive cases were included in this study. Neoadjuvant chemotherapy regimen containingtrastuzumab was applied to all patients. Patients’ age, gender, disease stage, tumor size and lymph node status, estrogen and progesterone receptorstatus, Ki-67 proliferation index, tumor grade, menopausal status and pathological complete response status after neoadjuvant therapy, neoadjuvanttreatment regimen and the relationship between the tumor and histological subtype were examined.Results: Grade III tumor, hormone receptor negativity, high Ki-67 score, and the presence of T3 or T4 tumor were found to be better associated withpathological complete response (p=0.036, p=0.033, p=0.021, p=0.048, respectively). High tumor grade, hormone receptor negativity and high Ki-67score were found as independent risk factors determining pathological complete response (p=0.043, p=0.047, p=0.035, respectively).Conclusion: In this series of 54 cases with HER2 positive breast cancer, the parameters determining pathological complete response after neoadjuvanttreatment are high Ki-67 proliferation index, grade III tumor and hormone receptor negativity.