In a multicentre, single-arm, phase 2 trial conducted by MD Anderson Cancer Center, carefully selected early stage #TNBC or #HER2 positive #breast_cancer patients (T1 or T2, N0 or N1) who achieved pCR to neoadjuvant systemic therapy (NST) avoided breast surgery and continued to standard radiotherapy. A total of 50 patients were enrolled and underwent image-guided vacuum-assisted core biopsy (VACB) following NST, pCR was achieved in 31 patients (62%). At a median follow-up of 26·4 months, no ipsilateral breast tumour recurrences occurred in these 31 patients. Meanwhile, additional prospective clinical trials evaluating this approach are needed.