AB134. SOH26AB_0429b. Oncological outcomes of sentinel lymph node biopsy versus targeted axillary dissection in node-positive breast cancer patients after neoadjuvant chemotherapy: a systematic review and meta-analysis

Background: Increasing evidence supports the oncologic safety of de-escalating axillary surgery after neoadjuvant chemotherapy (NAC). For patients with initially clinically node-positive (cN+) breast cancer whose axilla is down-staged after NAC (ycN0), sentinel lymph node biopsy (SLNB) or targeted axillary dissection (TAD) are acceptable approaches, but controversy remains regarding the optimal technique. The aim was to assess the oncological and survival outcomes of SLNB versus TAD for cN+ patients who convert to ycN0 after NAC.

Methods: A systematic literature search of relevant databases was conducted. A meta-analysis using the Mantel-Haenszel method was performed to calculate odds ratios (ORs) of axillary recurrence (AR), 3-year disease-free survival (DFS), and overall survival (OS) for SLNB compared with TAD.

Results: Five studies involving 2,849 patients (SLNB, n=1,842; TAD, n=1,007) were included. The rate of AR did not differ between SLNB and TAD [OR =1.23; 95% confidence interval (CI): 0.33–4.65; P=0.76]. Patients who underwent SLNB had a modestly reduced 3-year DFS (OR =1.53; 95% CI: 1.11–2.12; P=0.01) compared with those undergoing TAD. There was no difference in 3-year OS between SLNB and TAD (OR =2.12; 95% CI: 0.59–7.55; P=0.25).

Conclusions: Accurate axillary staging after NAC is important to guide adjuvant therapies. The rate of AR is very low and equivalent after SLNB or TAD for cN+ breast cancer patients who become ycN0 following NAC. Further studies are warranted to confirm whether TAD provides a clear survival advantage compared with SLNB on long-term follow-up.

Keywords: Axillary recurrence (AR); neoadjuvant chemotherapy (NAC); overall survival (OS); sentinel lymph node biopsy (SLNB); targeted axillary dissection (TAD)