Different strategies in de-escalation of axillary surgery in node-positive breast cancer following neoadjuvant treatment: a systematic review and meta-analysis of long-term outcomes.

Objective: Different surgical options existed in the management of axilla among breast cancer patients who were initially node-positive and were converted node-negative after neoadjuvant systemic treatment (NST). De-escalation of axillary surgery was feasible, but previous studies focused on the false-negative rate (FNR) of respective procedures. The aim of this study is to evaluate the oncological outcomes of sentinel lymph-node biopsy (SLNB), MARI procedure, and targeted axillary dissection (TAD).

Methods: PubMed, Embase, and the Cochrane library literature databases were searched systematically. Studies were eligible if they addressed the axillary recurrence rate of patients with nodal pathological complete response (pCR) and omission of axillary lymph-node dissection (ALND) after NST. Pooled analysis was performed using inverse variance methods for logit transformed proportions.

Results: Eleven retrospective studies and three prospective studies involving 4268 patients with node-positive breast cancers were included. A total of 1650 patients achieved nodal pCR and avoided ALND, 1382 patients with SLNB only and 268 patients with MARI/TAD. The pooled estimate of axillary recurrence was 2.1% (95%CI 1.4-3.2%) for patients with negative SLNB and 1.5% (95% CI 0.5-4.1%) for patients with negative MARI/TAD. There was no significant benefit of ALND over SLNB in patients with nodal pCR after NST. Pooled estimates of 5-year DFS, DDFS, and OS of SLNB alone were 0.87 (95% CI 0.83-0.90], 0.90 (95% CI 0.88-0.92), and 0.92 (95% CI 0.88-0.94), respectively.

Conclusions: Breast cancer patients who are converted node-negative after NST have extremely low nodal recurrence rate, irrespective of the choice of axillary surgery. Omission of ALND is oncologically safe in patients who have nodal pCR after NST.