Axillary surgery in patients with sentinel node macrometastases: secondary results of the randomized INSEMA trial

TL;DR

This study compares two surgical approaches for breast cancer patients with macrometastases in sentinel nodes and finds no significant difference in survival outcomes.

Contribution

The study provides new evidence on the non-inferiority of sentinel lymph node biopsy alone compared to full lymph node dissection in specific breast cancer patients.

Findings

No significant difference in invasive disease-free survival between the two surgical approaches.

Low locoregional recurrence rates in both treatment arms.

Overall survival rates were similar between the groups.

Abstract

The sub-study of the INSEMA trial (randomization-2) compares completion axillary lymph node dissection (cALND) with sentinel lymph node biopsy (SLNB) alone in cN0 patients with T1/T2 invasive breast cancer and one to three sentinel node macrometastases undergoing upfront breast-conserving surgery. The key secondary objective is to assess whether the SLNB-alone arm is non-inferior to cALND in terms of invasive disease-free survival (iDFS). Finally, 485 patients were recruited, and 386 patients (cALND: N = 169, SLNB alone: N = 217) were included in the per-protocol set. The median follow-up is 74.2 months. The 5-year iDFS analysis in the per-protocol set demonstrates a non-significant difference between study arms, with a hazard ratio (HR) of 1.69 (95% CI: 0.98-2.94) for SLNB alone compared to cALND. The 5-year iDFS rates are 86.6% (81.0%-90.7%) in the SLNB-alone arm and 93.8% (88.7%-96.6%) in the cALND arm (P = 0.058). The 5-year overall survival rates are 94.9% (90.6%-97.2%) in the SLNB-alone arm and 96.2% (91.7%-98.3%) in the cALND arm (P = 0.663). Locoregional recurrences (LRR) were infrequent, with 5-year incidence rates of 1.1% versus 0.0% (P = 0.405) in the SLNB-alone arm compared to cALND. In summary, no significant differences were observed between SLNB alone versus cALND for iDFS, overall survival, and LRR. Trial registration number: NCT02466737

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