Neoadjuvant chemotherapy (NACT) is increasingly being used to treat early breast cancer, and offers several advantages, including reducing the extent of breast and axillary surgery, and providing an in vivo assessment of tumour sensitivity to treatment1–4. Clinical trials have identified tumour subgroups with high rates of pCR. A pCR can be achieved in 45–90 per cent of human epidermal growth factor receptor 2-positive (HER2+) tumours and triple-negative breast cancer (TNBC), but the rate in oestrogen receptor-positive (ER+)/HER2-negative (HER2–) breast cancer remains below 10 per cent3,5. Historically, increasing pCR rates following NACT have not translated into more breast-conserving surgery (BCS), but more recent data suggest that NACT can result in surgical downstaging6.