Accuracy of core biopsy in predicting pathologic complete response in the breast in patients with complete/near complete clinical and radiological response (Complete Responders in the Breast – CRBr) – Trial design and conduct

INTRODUCTION: With the advent of taxanes and targeted agents in neoadjuvant chemotherapy (NACT) for breast cancer, the rates of pathologic complete response (pCR) have been steadily increasing. One of the roles of surgery in these women is to serve as a biopsy to confirm or negate a pCR. DESIGN: This is a prospective validation study. All newly diagnosed non-metastatic breast cancers, of any luminal subtype, planned for neoadjuvant chemotherapy (NACT) with a titanium clip placed in the tumor, will be screened. Eligible patients who have a complete/near complete response to NACT as seen on a mammogram and ultrasound of the breast, will undergo multiple core biopsies of the tumor bed under ultrasound guidance as an outpatient procedure. A minimum of four core biopsy specimens will be mandatory. An MRI will also be done for these patients for documentation and analysis. The core biopsy will be compared to the final histopathology report after definitive surgery. OBJECTIVES: The objective is to study the false negative rate and accuracy of ultrasound guided core biopsies of the tumor bed in predicting pCR. Additionally, the correlation of pCR in the breast with axillary response and the incremental benefit of an MRI in predicting pCR will be evaluated. DISCUSSION: The concept of using image guided core biopsies to predict pCR could be useful in designing future studies aimed at avoiding redundant surgery in women with a complete response to NACT. This study is registered with Clinical Trials Registry of India (CTRI/2018/01/011122).