Updated results from the phase III SENOMAC trial suggest that many patients with early-stage breast cancer and limited spread to sentinel lymph nodes can safely forgo axillary lymph node dissection (ALND), avoiding substantial long-term arm morbidity without compromising survival. The findings were presented at the 2026 ASCO Annual Meeting (Abstract LBA503).
Study Details
The international study enrolled 2,540 patients from Sweden, Denmark, Germany, Greece, and Italy with T1 to T3 breast cancer and one or two sentinel lymph node macrometastases. Participants were randomly assigned to undergo either completion ALND (n = 1,205) or omission of ALND (n = 1,335) after sentinel lymph node biopsy. More than one-third of patients underwent mastectomy, a population for whom evidence supporting omission of ALND has previously been limited.
Key Results
After a median follow-up of 60.1 months, survival outcomes were nearly identical between the two groups. Five-year overall survival was 93.4% among patients who underwent ALND and 94.4% among those who did not. Five-year breast cancer–specific survival was similarly high, at 97.2% and 97.9%, respectively. Overall, 203 participants died during follow-up, including 74 deaths attributed to breast cancer.
The study’s findings reinforce the growing body of evidence suggesting that more extensive axillary surgery does not improve outcomes for patients with limited nodal disease who receive contemporary systemic therapy and regional nodal irradiation. According to lead investigator Jana de Boniface, MD, PhD, of Capio St. Göran’s Hospital and Karolinska Institutet in Sweden, “The key finding is that more axillary surgery in itself does not improve survival in these patients. This is extremely important because it means that axillary surgery should be seen as a diagnostic instrument, not a therapeutic tool.”
Omission of ALND resulted in significantly better patient-reported arm function and fewer arm-related symptoms over time. Arm morbidity was assessed using the Lymph-ICF questionnaire and the EORTC QLQ-BR23 breast cancer–specific quality-of-life instrument at 1, 3, and 5 years after randomization. Patients who avoided ALND consistently reported better outcomes across all assessments. On the Lymph-ICF scale, average score differences favoring omission of ALND were 10.64 points at 1 year, 10.73 points at 3 years, and 10.75 points at 5 years. Similarly, EORTC arm symptom scores favored omission of ALND by 10.90, 9.86, and 10.02 points at the same respective time points.
The findings address an important clinical issue because ALND has long been associated with chronic pain, numbness, restricted arm mobility, and lymphedema. Investigators noted that nearly one in five patients who undergo ALND report moderate arm dysfunction 5 years after surgery, and 13% report severe or very severe impairment.
DISCLOSURE: For full disclosures of the study authors, visit coi.asco.org.
