Selective De-escalation of Axillary Surgery Post Neoadjuvant Chemotherapy in Breast Cancer-Are We Ready?

Newer systemic treatments are driving us towards axillary conservation to reduce morbidity and enhance quality of life without oncological compromise in breast cancer (BC) patients. It is important to identify which patients might benefit from a more conservative approach to the axilla by studying the neoadjuvant chemotherapy (NACT) responses in different subgroups. The aim of the study is to evaluate real-world pathological response rates in breast cancer patients in accordance with latest NACT regimes and also to identify the subsets ideal for axillary de-escalation. This single-centre study at Sri Shankara Cancer Hospital and Research Centre, Bangalore, reviewed a prospectively maintained database from January 2023 to May 2024 including all non-metastatic BC patients undergoing surgery after recommended NACT. A total of 224 patients were included for analysis. Pathological complete response (PCR) was achieved by 31.69% (71/224), with 55.3% (124/224) achieving axillary PCR (APCR) and 35.26% (79/224) achieving breast PCR (BPCR). According to subtypes, 65.11% PCR was observed in Her2 subtype, followed by 44.2% in the triple positive, 24.4% in triple negative and 10% in hormone receptor positive. Among patients with cN0 disease, 91.3% (21/23) had APCR, while 63.2% (91/144) of cN1 patients were down-staged to ypN0 and only 17.9% (7/39) of cN2 down-staged to cN0. Combining the Her2-positive and triple-positive groups, 96.2% (51/53) of patients with BPCR had APCR. Pre NACT clinical nodal stage, ER and Her2 neu status can predict APCR with sensitivity of 74.0% with CI of 95% and specificity of 69.0% with CI of 95%. Our study suggests that HER2-positive and triple-positive patients with cN0 and cN1 converted to cN0 are potential candidates for de-escalation of axillary surgery.