Axillary Nodal Upstaging in cT1N0 Invasive Lobular Carcinoma: Evaluating Applicability of SOUND Trial Results
In brief
Nearly 18% of ultrasound-negative lobular breast cancers had positive nodes
In a retrospective study of 639 patients with early, hormone-sensitive invasive lobular breast cancer and normal axillary ultrasound, 17.7% had cancer in sentinel nodes, but only 2.3% had extensive nodal disease. The rate of any nodal involvement was similar to rates in trials of sentinel node biopsy omission, but this study did not test omission; lymphovascular invasion was the strongest independent marker of nodal spread.
- Journal
- Annals of surgery (Q1)
- Published
- 28 September 2026
- Study design
- Randomized controlled trial
- Evidence level
- Level 1, High (CEBM 1b)
- Authors
- Thomas Amburn, Anita Mamtani, Jane J Chen, Varadan Sevilimedu, Sherry Shen, Komal Jhaveri, et al.
- PMID
- 42802378
- DOI
- 10.1097/SLA.0000000000007227
Why clinicians should know about it
- Picked for Breast and Endocrine Surgery (paper of the day, 29 September 2026): Axillary nodal positivity in SOUND‑eligible invasive lobular carcinoma
Abstract
OBJECTIVE: To determine whether sentinel lymph node biopsy (SLNB) omission is applicable to stage 1 invasive lobular breast cancer (ILC). BACKGROUND: The SOUND and INSEMA randomized controlled trials demonstrated that SLNB omission is noninferior to performing SLNB in early-stage, clinically node-negative (cT1-2N0), hormone receptor-positive/HER2-negative (HR+/HER2-) patients with breast cancer with negative preoperative axillary ultrasound. However, the applicability of SLNB omission in ILC has been uncertain. METHODS: We retrospectively identified patients with cT1N0, HR+/HER2- pure ILC, and normal axillary ultrasound who underwent upfront surgery with SLNB between 2009 and 2024. Clinicopathologic characteristics and pathologic nodal burden were evaluated. RESULTS: Six hundred thirty-nine patients met the inclusion criteria, of whom the majority were postmenopausal women (72%) with low- to intermediate-grade (88%) and/or classic-type (84%) ILC. Axillary nodal metastases were identified on surgical pathology in 113 (17.7%) patients: 24 (3.8%) pN1mic, 74 (11.6%) pN1, 8 (1.2%) pN2, and 7 (1.1%) pN3. Node-positive patients were more often younger, premenopausal (36% vs. 26%, P=0.035), and presented with larger pathologic tumor size (46.7% vs. 18.3% pT2-3, P<0.001) and lymphovascular invasion (LVI) (19% vs. 3.2%, P<0.001). On univariate analysis, premenopausal status, high grade, and LVI were independently associated with nodal positivity. On multivariate analysis, only LVI remained independently associated with nodal positivity. CONCLUSIONS: Among patients with SOUND-eligible ILC, 17.7% had axillary nodal metastasis and only 2.3% had extensive axillary nodal metastasis. These findings are comparable to the node-positive rates reported in the SLNB arm of the SOUND (13.7%) and INSEMA (15.1%) trials. High-risk features such as LVI and high grade were associated with nodal positivity.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.