Abstract PS4-11-07: Residual axillary disease in Node-Positive Breast Cancer Patients After Neoadjuvant systemic therapy- A Single centre Retrospective Study

Abstract Background Axillary lymph node status is an integral prognostic factor in breast cancer treatment and steers the decisions on local, regional and systemic treatments. Advances in neoadjuvant chemotherapy has led to de-escalation of axillary surgery in patients with N0-N1 disease. Residual axillary lymph node (LN) metastasis after neoadjuvant chemotherapy (NACT) generally warrants axillary lymph node dissection (ALND). We investigated the risk of having additional metastases in the axilla when the lymph nodes are removed by targeted axillary dissection (TAD) harboured metastases after NACT. We aimed to identify subgroups suitable for de-escalated axillary treatment. Methods We conducted a retrospective audit of 82 consecutive patients that underwent targeted axillary dissection post neoadjuvant chemotherapy at our centre from January 2019 to December 2023. The data was extracted from patient electronic medical records following patient confidentiality and data protection guidelines. The study has been approved by the trusts governance team. Results Eighty two patients were included in our retrospective study. The median age was 49 years (range 34-68). Among the 82 patients, there was only one failed identification of the clipped node leading to a primary ALND. Forty patients (49.4%) did not have involved nodes on the targeted axillary dissection (TAD). In our cohort 41 (50.6%) patients had a positive TAD. Thirty eight patients (46.3%) were hormone receptor positive and HER 2 negative. Triple negative breast cancers were found in 13 patients (15.9%) and 28 patients (34.2 %) had HER 2 positive disease. There was no statistically significant correlation with the cancer type or receptor status. Among 44 patients undergoing ALND after positive TAD, 13 (29.5%) had further residual disease in the axilla. Breast complete pathologic response did not correlate with the residual disease in the axilla, allowing for the small sample limitation. Conclusion TAD lymph node positivity is independent of the receptor subtype as shown by our study. We conclude that TAD may be considered for de-escalation of axillary surgery in all histological receptor subtypes. Our study findings are consistent with other similar studies. However, further studies are required with a larger sample size to validate and confirm these findings. Citation Format: Q. A. Chougle, C. Kalyvioti, A. Amylidi, N. Alluhaydan, A. Saleeb, G. Bitsakou, E. Shaari, H. Hamed, K. Cox. Residual axillary disease in Node-Positive Breast Cancer Patients After Neoadjuvant systemic therapy- A Single centre Retrospective Study abstract. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS4-11-07.