Omitting sentinel lymph node biopsy (SLNB) appears safe for select patients with early-stage, hormone receptor (HR)–positive, HER2-negative breast cancer, according to results from the Dutch phase 3 BOOG 13-08 trial (NCT02271828) presented at the 2025 San Antonio Breast Cancer Symposium.
The trial included patients aged 50 years or older with grade 1 or 2, stage cT1–2N0 breast cancer. After a median follow-up of five years, outcomes in patients who skipped SLNB (n = 824) were comparable to those who underwent the procedure (n = 748). Local recurrence occurred in 9.1% of patients without SLNB versus 15.3% with SLNB, while regional recurrence rates were 9.1% versus 5.1%, respectively. Contralateral breast cancer and distant metastasis rates were 12.5% and 29.5% in the no-SLNB group, compared with 22.0% and 23.7% in the SLNB group.
Deaths among patients who did not undergo SLNB were most commonly due to second non-breast cancers (46%) and progressive or metastatic breast cancer (37%). In the SLNB group, 35% died from second non-breast cancers and 30% from progressive breast cancer.
“These findings indicate that SLNB omission may be safely considered for patients over 50 with HR-positive, grade 1/2, T1 tumors,” said lead author Marjolein Smidt, MD, PhD, professor of surgical oncology at Maastricht University Medical Center. She noted that endocrine therapy was not required for the no-SLNB approach in this subset, though longer follow-up is needed for patients with T2 tumors.
The trial enrolled 1,733 women across 25 Dutch centers from 2015 to 2022. All patients underwent breast-conserving surgery and whole-breast radiation. Post-surgery, patients either received SLNB (arm A; n = 748) or no SLNB (arm B; n = 824). Axillary treatment and systemic therapy were provided as indicated. The median age was 61.9 years; 83% had T1 tumors, 82% had grade 1/2 disease, and 86% of sentinel nodes were negative.
Five-year regional recurrence-free survival was 96.6% in the SLNB group versus 94.2% in the no-SLNB group, an absolute difference of 2.35%. Five-year distant disease-free survival was 96.0% versus 92.9%, a difference of 3.3%. Smidt confirmed that noninferiority thresholds were not exceeded.
Findings align with prior studies, including SOUND (NCT02167490) and INSEMA (NCT02466737), which reported similarly low recurrence and mortality rates among HR-positive, HER2-negative patients over 50 who skipped SLNB.
“These results support a less invasive approach to axillary management in carefully selected patients,” Smidt said.
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