Surgery · Medical Literature
Omission of axillary lymph node dissection in ultrasound-detectable axillary metastases in primary breast cancer treated by upfront surgery: prospective randomized SENOMAC-ULTRA non-inferiority trial.
Abstract
Axillary lymph node dissection (ALND) in breast cancer causes substantial arm morbidity and long-term functional impairment. Less extensive axillary surgery, such as targeted axillary dissection (TAD), significantly reduces this risk. Although omission of ALND is standard in clinically node-negative disease with limited sentinel node involvement, this is not the case for patients with clinically node-positive disease undergoing upfront surgery. The aim of the SENOMAC-ULTRA trial is to evaluate whether TAD can safely replace ALND in patients with clinically node-positive breast cancer receiving upfront surgery. SENOMAC-ULTRA is a prospective, international, multicentre, randomized non-inferiority trial. Adults with stage II-III invasive breast cancer and axillary metastases detectable by ultrasound and confirmed by fine needle aspiration or core biopsy are eligible for inclusion. Participants are randomized 1 : 1 to TAD (removal of marked metastatic nodes plus sentinel lymph node biopsy) or standard ALND. The primary endpoint is recurrence-free survival, assessed for non-inferiority using a Cox proportional hazards model. Secondary endpoints include overall survival, locoregional recurrence, regional nodal recurrence, distant relapse-free survival, invasive breast cancer-free survival, patient-reported arm morbidity, and health-related quality of life, as well as performance measures of axillary ultrasound and marking techniques. A sample size of 1380 patients has been calculated to provide 81% power to exclude a hazard ratio > 1.47 for recurrence-free survival at 5 years, adopting a non-inferiority margin of 4.5%. Follow-up is planned for 10 years. The trial protocol has been approved by the Swedish Ethical Review Authority (Dnr 2025-07730-01); each participating country will obtain local ethics approval. It is anticipated that the SENOMAC-ULTRA trial will fill an important knowledge gap guiding the surgical management of patients with clinically node-negative breast cancer. Registration number: NCT06869629 (https://clinicaltrials.gov).
Clinical relevance
In adult patients with stage II–III invasive breast cancer and ultrasound-detectable, biopsy-confirmed axillary metastases undergoing upfront surgery, is targeted axillary dissection (TAD) non-inferior to standard axillary lymph node dissection (ALND) with respect to recurrence-free survival? __SNAPSHOT__ {"studyDesign":"Prospective, international, multicentre, randomized non-inferiority trial (protocol publication — no outcome results reported to date)","setting":"International, multicentre; specific countries and institutions not fully enumerated in the abstract. The broader SENOMAC program originates from Sweden and spans multiple European countries.","sampleSize":"Not reported in this protocol publication; target accrual not specified in the supplied abstract.","population":"Adults with stage II–III primary invasive breast cancer with axillary nodal metastases detectable by ultrasound and confirmed by fine needle aspiration or core biopsy, planned for upfront (non-neoadjuvant) surgery. This represents a clinically node-positive (cN+) population, which is explicitly excluded from prior de-escalation trials such as SENOMAC (which enrolled only clinically node-negative patients).","intervention":"Targeted axillary dissection (TAD): removal of the clip-marked, biopsy-proven metastatic node(s) combined with sentinel lymph node biopsy (SLNB).","comparator":"Standard complete axillary lymph node dissection (ALND).","primaryOutcome":"Recurrence-free survival, assessed for non-inferiority using a Cox proportional hazards model.","followUp":"Not reported in the abstract; long-term follow-up is expected given the non-inferiority survival endpoint.","fundingSource":"Not reported in the supplied abstract. The parent SENOMAC program has been funded by non-profit/government sources (Swedish Cancer Society, Swedish Research Council, Nordic Cancer Union, Swedish Breast Cancer Association), but specific SENOMAC-ULTRA funding is not confirmed from the abstract."}
Key findings
This is a protocol/design publication. No efficacy, safety, or patient-reported outcome data are presented. The abstract describes trial rationale, eligibility criteria, intervention arms, randomization scheme (1:1), and the primary endpoint (recurrence-free survival via Cox proportional hazards non-inferiority model). Secondary endpoints include overall survival and locoregional recurrence (abstract text truncated; full secondary endpoint list not available). No effect sizes, confidence intervals, p-values, hazard ratios, NNT, NNH, or adverse event data are reported. The non-inferiority margin has not been specified in the supplied abstract text. The clinical rationale presented is that approximately half of patients with ultrasound-detectable axillary metastases undergoing upfront surgery are estimated to have limited nodal involvement (1–2 positive nodes) for whom full ALND may be unnecessarily extensive, based on observational data cited in the broader literature.
Practice implications
SENOMAC-ULTRA is a hypothesis-generating protocol that formally extends the surgical de-escalation question into a population not addressed by prior landmark trials (ACOSOG Z0011, AMAROS, SENOMAC): patients with pre-operatively confirmed, ultrasound-detectable axillary metastases (cN1) undergoing upfront surgery. Prior trials, including the parent SENOMAC trial (n=2,540–2,766, clinically node-negative population), established non-inferiority of SLNB alone versus complete ALND after intraoperative detection of 1–2 sentinel node macrometastases, with meaningful reductions in arm morbidity. However, those findings cannot be directly extrapolated to patients with pre-operatively biopsy-confirmed nodal disease, who are categorically node-positive, may harbor greater nodal burden, and have historically been directed to mandatory ALND. SENOMAC-ULTRA addresses this gap by testing whether TAD — a more precise, less morbid procedure that retrieves the known metastatic node(s) alongside sentinel nodes — can safely replace ALND in this cN+ upfront surgical population. No patients have been reported as enrolled or followed up in this publication. Critically, which patients will and will not be adequately represented (e.g., by tumor biology, nodal burden, receipt of radiotherapy, or race/ethnicity) cannot be assessed from a protocol paper. Practice should not change based on this publication; it defines the scientific question, not the answer. IMPORTANT LIMITATION: Only the abstract of this protocol publication was available for review; the full article may contain additional methodological detail, sample size calculations, non-inferiority margin specifications, and planned subgroup analyses not captured here. __LIMITATIONS__ 1. This is a trial protocol paper — no outcome data are presented, and no conclusions about efficacy, safety, or clinical utility of TAD versus ALND in cN+ upfront surgery can yet be drawn. 2. The supplied abstract is truncated; secondary endpoints, non-inferiority margin, and planned sample size are incompletely described, precluding full methodological appraisal. 3. The target population (cN+ upfront surgery) has higher a priori nodal burden than prior de-escalation trial populations; residual disease rates after TAD may be substantially higher than after SLNB in cN0 patients, raising concerns about adequacy of regional control that the trial is designed but not yet powered to address in this abstract. 4. Generalizability will depend on the eligibility criteria and adjuvant radiotherapy protocols ultimately employed, which are not fully specified in the abstract. 5. Blinding is not feasible for a surgical intervention trial, introducing potential performance and detection bias. 6. The role of adjuvant nodal radiotherapy — a critical effect modifier in parent SENOMAC — is not specified in the supplied abstract, yet it substantially influences the oncological safety of axillary de-escalation. 7. Racial and ethnic diversity of the anticipated trial population is not reported. 8. Funding source for SENOMAC-ULTRA is not confirmed in this abstract, precluding assessment of industry sponsorship bias. __BOTTOM_LINE_CATEGORY__ not_ready_for_clinical_application __BOTTOM_LINE__ SENOMAC-ULTRA is a rigorously designed prospective randomized non-inferiority trial testing whether targeted axillary dissection (TAD) can safely replace full ALND in clinically node-positive breast cancer patients with ultrasound-detected, biopsy-confirmed axillary metastases undergoing upfront surgery — a population for whom evidence-based surgical de-escalation data do not yet exist. This publication establishes the trial protocol and rationale; no outcome data are available. Clinicians should not alter practice based on this paper, but should be aware that SENOMAC-ULTRA represents the next critical frontier in axillary surgical de-escalation research.