Breast
SENOMAC closes the loop on axillary management in cN0 pts with SN macrometastases, broadening surgical de-escalation to populations Z0011 couldn't address.
SENOMAC NCT02240472
ForcN0 breast cancer, T1-T3, 1-2 SN macrometastases, BCT or mastectomy
TL;DR5yr RFS 89.7% vs 88.7%, HR 0.89: SNB alone noninferior to ALND in cN0 breast cancer with 1-2 SN macrometastases.
vs leading data
- vs ACOSOG Z0011: SENOMAC resolves Z0011's power deficit, uncertain RT volumes, and short f/u in one trial
- vs AMAROS: AMAROS replaced ALND with axillary RT; SENOMAC omits axillary-directed treatment entirely, relying on regional nodal RT
7 details
Methods
- 🔍 Phase 3 NI RCT, N=2766 enrolled, 2540 per-protocol; median f/u 46.8mo (range 1.5-94.5)
- 🔍 Extends Z0011 eligibility: includes mastectomy, T3 tumors, extracapsular extension, male pts
- 🔍 Nodal RT administered in 89.9% SNB-only group, 88.4% ALND group
Results
- 📊 2° EP (RFS): 5yr 89.7% (95% CI 87.5-91.9) SNB-only vs 88.7% (95% CI 86.3-91.1) ALND
- 📐 Country-adjusted HR 0.89 (95% CI 0.66-1.19); noninferiority p<0.001 (upper CI 1.19 below margin 1.44)
Critique
- ⚠️ 1° EP (OS) not yet reported; only prespecified secondary RFS analysis shown here
- ⚠️ Near-universal nodal RT in both arms: noninferiority may not hold where nodal RT is routinely omitted
Open questions
- Primary OS endpoint results still pending
- Generalizability in settings where nodal RT is not routinely administered
- Optimal RT volumes (high-tangent vs dedicated nodal fields) in SNB-only pts
📚 Sources · 📄 1 paper
Omitting Axillary Dissection in Breast Cancer with Sentinel-Node Metastases
Abstract
BACKGROUND<br/>Trials evaluating the omission of completion axillary-lymph-node dissection in patients with clinically node-negative breast cancer and sentinel-lymph-node metastases have been compromised by limited statistical power, uncertain nodal radiotherapy target volumes, and a scarcity of data on relevant clinical subgroups.<br/>METHODS<br/>We conducted a noninferiority trial in which patients with clinically node-negative primary T1 to T3 breast cancer (tumor size, T1, ≤20 mm; T2, 21 to 50 mm; and T3, >50 mm in the largest dimension) with one or two sentinel-node macrometastases (metastasis size, >2 mm in the largest dimension) were randomly assigned in a 1:1 ratio to completion axillary-lymph-node dissection or its omission (sentinel-node biopsy only). Adjuvant treatment and radiation therapy were used in accordance with national guidelines. The primary end point was overall survival. We report here the per-protocol and modified intention-to-treat analyses of the prespecified secondary end point of recurrence-free survival. To show noninferiority of sentinel-node biopsy only, the upper boundary of the confidence interval for the hazard ratio for recurrence or death had to be below 1.44.<br/>RESULTS<br/>Between January 2015 and December 2021, a total of 2766 patients were enrolled across five countries. The per-protocol population included 2540 patients, of whom 1335 were assigned to undergo sentinel-node biopsy only and 1205 to undergo completion axillary-lymph-node dissection (dissection group). Radiation therapy including nodal target volumes was administered to 1192 of 1326 patients (89.9%) in the sentinel-node biopsy–only group and to 1058 of 1197 (88.4%) in the dissection group. The median follow-up was 46.8 months (range, 1.5 to 94.5). Overall, 191 patients had recurrence or died. The estimated 5-year recurrence-free survival was 89.7% (95% confidence interval [CI], 87.5 to 91.9) in the sentinel-node biopsy–only group and 88.7% (95% CI, 86.3 to 91.1) in the dissection group, with a country-adjusted hazard ratio for recurrence or death of 0.89 (95% CI, 0.66 to 1.19), which was significantly (P<0.001) below the prespecified noninferiority margin.<br/>CONCLUSIONS<br/>The omission of completion axillary-lymph-node dissection was noninferior to the more extensive surgery in patients with clinically node-negative breast cancer who had sentinel-node macrometastases, most of whom received nodal radiation therapy. (Funded by the Swedish Research Council and others; SENOMAC ClinicalTrials.gov number, NCT02240472.)