Multicenter phase 2 trial of eliminating surgery after exceptional response of invasive breast cancer to neoadjuvant systemic therapy

Neoadjuvant systemic therapy (NST) for triple-negative and HER2-positive breast cancer yields a pathological complete response (pCR) in approximately 60% of patients. pCR, associated with an excellent prognosis, can be accurately determined by percutaneous image-guided vacuum-assisted core biopsy (VACB). A multicenter phase 2 trial by the Exceptional Responders Clinical Trials Group evaluated radiotherapy alone, without breast surgery, in patients with early-stage triple-negative or HER2-positive breast cancer after image-guided VACB-determined pCR to NST. At a median follow-up of 26.4 months (IQR 15.2-39.6) no ipsilateral breast tumor recurrences occurred in these patients. The authors conclude that eliminating breast surgery in highly selected patients with an image-guided VACB-determined pCR to NST was feasible with promising early results.