Clinical Report: 2026 ASCO Breast Cancer Highlights: SENOMAC

Overview

Harold Burstein, MD, PhD, and Laura S. Dominici, MD, FACS, discuss the SENOMAC trial and whether completion axillary lymph node dissection can be omitted for selected patients with early breast cancer and limited sentinel-node involvement. The supplied meeting-abstract title identifies overall survival and patient-reported arm morbidity as outcomes; no trial results or numerical data are provided in the source material.

Background

Axillary surgery is used to assess and manage regional lymph-node disease in early breast cancer. Completion axillary lymph node dissection can be avoided in some patients with limited sentinel-node involvement, with eligibility depending on clinical and treatment context. The 2025 ASCO guideline update advises against recommending dissection for patients with one to two positive sentinel nodes undergoing breast-conserving surgery and whole-breast radiotherapy, and permits omission after mastectomy when postmastectomy radiotherapy with regional nodal irradiation is given. The SENOMAC discussion addresses this de-escalation question in patients with limited nodal involvement.

Data Highlights

The supplied material provides no SENOMAC outcome estimates, participant counts, or other numerical trial results. The meeting abstract is titled “Omission of completion axillary dissection in patients with breast cancer and sentinel lymph node macrometastases: Overall survival and patient-reported arm morbidity from the randomized SENOMAC trial.”

Key Findings

• The video context identifies Harold Burstein, MD, PhD, and Laura S. Dominici, MD, FACS, as discussing SENOMAC.
• The stated clinical question is whether some patients with early breast cancer and limited lymph-node involvement can avoid additional axillary surgery.
• The related SENOMAC meeting abstract concerns omission of completion axillary dissection in patients with sentinel-node macrometastases.
• The abstract title specifies overall survival and patient-reported arm morbidity as outcomes, but the supplied material does not report their results.
• The 2025 ASCO guideline update advises against ALND for early-stage disease with one to two positive sentinel nodes when breast-conserving surgery and whole-breast radiotherapy are used.
• The ASCO update also allows omission of ALND after mastectomy with one to two positive sentinel nodes when postmastectomy radiotherapy with regional nodal irradiation is given.

Clinical Implications

The supplied ASCO guidance supports omission of ALND in specified treatment settings for patients with one to two positive sentinel nodes. The source material does not provide SENOMAC results, so it does not establish additional trial-specific conclusions about survival or arm morbidity.

Conclusion

SENOMAC addresses whether completion axillary dissection can be omitted in patients with breast cancer and sentinel-node macrometastases. The provided material identifies the trial’s outcomes of interest but does not include its findings.

Related Resources & Content

1. SENOMAC investigators, ASCO Publications, 2026 — Omission of completion axillary dissection in patients with breast cancer and sentinel lymph node macrometastases: Overall survival and patient-reported arm morbidity from the randomized SENOMAC trial
2. ASCO, PubMed, 2025 — Sentinel Lymph Node Biopsy in Early-Stage Breast Cancer: ASCO Guideline Update
3. Giuliano et al., JAMA, 2017 — Effect of Axillary Dissection vs No Axillary Dissection on 10-Year Overall Survival Among Women With Invasive Breast Cancer and Sentinel Node Metastasis: The ACOSOG Z0011 (Alliance) Randomized Clinical Trial
4. SENOMAC investigators, New England Journal of Medicine — Omitting Axillary Dissection in Breast Cancer with Sentinel-Node Metastases
5. The ASCO Post — SABCS 2025: High-Level Review of Select Data
6. The ASCO Post — SABCS 2025: High-Level Review of Select Data
7. The ASCO Post — SABCS 2025: High-Level Review of Select Data
8. Sentinel Lymph Node Biopsy in Early-Stage Breast Cancer: ASCO Guideline Update
9. Omission of completion axillary dissection in patients with breast cancer and sentinel lymph node macrometastases: Overall survival and patient-reported arm morbidity from the randomized SENOMAC trial
10. Effect of Axillary Dissection vs No Axillary Dissection on 10-Year Overall Survival Among Women With Invasive Breast Cancer and Sentinel Node Metastasis: The ACOSOG Z0011 (Alliance) Randomized Clinical Trial | Surgery | JAMA | JAMA Network
11. Omitting Axillary Dissection in Breast Cancer with Sentinel-Node Metastases | New England Journal of Medicine