Research in context
Evidence before this study
We searched PubMed for studies published in English from database inception to Aug 1, 2022, on omission of breast cancer surgery following neoadjuvant systemic therapy (NST). Searches were intentionally broad and included the terms “breast cancer” AND “radiation” AND “neoadjuvant chemotherapy” AND (“surgery” OR “biopsy” OR “complete response” OR “pathologic complete response”). We identified several retrospective and a few prospective single-institution and multi-institutional studies evaluating radiotherapy as the definitive local modality after NST. These studies collectively showed unacceptably high locoregional failure rates. These poor outcomes were due to restricted or no use of rudimentary breast imaging techniques, the inability of breast imaging to accurately identify patients who would have a pathological complete response, and poor of knowledge of the molecular subtypes most likely to be associated with an exceptional response. We have recently shown that image-guided vacuum-assisted core biopsy (VACB) can accurately identify patients likely to have a pathological complete response after NST. Other studies using different eligibility and biopsy techniques have shown less robust performance. One previous retrospective study used core biopsy to select patients who might have a pathological complete response after NST. In that study, which showed a high local failure rate in patients who underwent radiotherapy but not surgery after NST, core needle biopsies were done randomly by non-image-guided biopsy of the breast at the time of axillary surgery following NST. Thus, the overall quality of the previous evidence was moderately low (level 3–4). No data from long-term, prospective studies or modern, randomised trials were found.
Added value of this study
To our knowledge, this study is the first modern, prospective trial of omission of surgery in patients with early-stage breast cancer (triple-negative breast cancer and HER2-positive breast cancer) who are exceptional responders to NST as indicated by state-of-the art breast imaging-guided VACB. Compared with previous trials, this modern trial had improved systemic therapy and selective image-guided VACB with stringent histological processing. The protocol-specified early results of this trial suggest that this new potential treatment approach appears promising.
Implications of all the available evidence
Long-term data to corroborate the early results of this trial, taken together with previous historical results and other results from prospective, single-centre, multi-institutional, and cooperative group trials, are necessary before this novel de-escalated treatment approach can become standard of care in this patient population.