Current practice and surgical outcomes of neoadjuvant chemotherapy for early breast cancer: UK NeST study

This prospective multicentre cohort study aimed to determine surgical decision-making in the breast and axilla, as well as pathological complete response (pCR) rate in patients undergoing neoadjuvant chemotherapy (NACT). 1283 patients were recruited from 39 UK breast units (Dec 2017-Nov 2018). Complete histopathological and surgical outcomes were available for 900 patients. Overall pCR rate in the breast was 41.4%, with pCR rate of 36% in node positive tumours (ypT0/is, ypN0). Based on tumour subtype, pCR rate was highest in HER2+ tumours (70.2% for ER-HER2+ and 47.3% for ER+HER2+), 41.9% for triple negative breast cancer (TNBC), and 14.9% for ER+HER2- tumours. At diagnosis, 486 tumours were ineligible for breast conserving surgery (BCS) whereas 350 were deemed suitable for BCS. Following NACT, 176/486 (36.2%) of these tumours were converted from mastectomy to BCS due to sufficient disease downstaging. The intention to resect the original tumour footprint was stated by 44.8%, whereas 55.2% stated the intention to resect the post-treatment tumour footprint. Margin positivity rate was 11.4% with final overall mastectomy rate of 45.9% when re-excisions were considered. With regards to the axilla, most patients with cN0 disease underwent SLNB post-NACT (82.9%). For the 405 patients who underwent SLNB post-NACT, positive nodes were detected in 7.4% on pathology assessment. For the 385 patients who received axillary node clearance post-NACT, 186 patients (48.3%) were found to have negative nodes on pathology assessment.

Classifications: Adjuvant & Neoadjuvant Treatment

Keywords: Neoadjuvant Chemotherapy/ NACT Early Breast Cancer Trials