Long-term standard sentinel node biopsy after neoadjuvant treatment in breast cancer: a single institution ten-year follow-up

Introduction: In patients with positive lymph nodes (cN+) prior to neoadjuvant treatment (NAT), which convert to a clinically negative axilla (cN0) after treatment, the use of sentinel node biopsy (SNB) is still debatable, since the false-negative rate (FNR) is significantly high (12.6-14.2%). The objective of this retrospective mono-institutional study, with a long follow-up, aimed to evaluate the outcome in patients undergoing NAT who remained or converted to cN0 and received SNB independent of target axillary dissection (TAD) or the removal of at least 3 sentinel nodes (SNs). Methods: This study analyzed 688 consecutive cT1-3, cN0/1/2 patients, operated at the European Institute of Oncology, Milan, from 2000 to 2015 who became or remained cN0 after NAT and underwent SNB with a least one SN found. Axillary dissection (AD) was not performed if the SN was negative. Nodal radiotherapy (RT) was not mandatory. Results: Axillary failure occurred in 1.8% of the initially cN1/2 patients and in 1.5% of the initially cN0 patients. After a median follow-up of 9.2 years (IQR 5.3-12.3), the 5-and 10-year overall survival (OS) were 91.3% (95% CI, 88.8-93.2) and 81.0% (95% CI, 77.2-84.2) in the whole cohort, 92.0% (95% CI, 89.0-94.2) and 81.5% (95% CI, 76.9-85.2) in those initially cN0, 89.8% (95% CI, 85.0-93.2) and 80.1% (95% CI, 72.8-85.7) in those initially cN1/2. Conclusion: The 10-year follow-up confirmed our preliminary data that the use of standard SNB is acceptable in cN1/2 patients who become cN0 after NAT and will not translate into a worse outcome. (c) 2020 Elsevier Ltd, BASO -The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.

Automated summary

This study evaluated the outcomes of patients undergoing NAT who remained or converted to cN0 and received SNB, showing a high overall survival rate after 10-year follow-up. The use of standard SNB in cN1/2 patients who become cN0 after NAT was deemed acceptable and did not result in worse outcomes.