As reported in The New England Journal of Medicine by de Boniface et al, the phase III SENOMAC trial showed noninferiority in recurrence-free survival with sentinel node biopsy alone vs completion axillary node dissection in patients with breast cancer and sentinel node metastases.
Study Details
In the trial, 2,540 patients in the per-protocol population from sites in Sweden, Denmark, Germany, Greece, and Italy were randomly assigned between January 2015 and December 2021 to receive sentinel node biopsy only (n = 1,335) or completion axillary node dissection (n = 1,205). Patents had to have clinically node-negative, T1-T3 disease with one or two sentinel node macrometastases (> 2 mm in largest dimension).
Patients received adjuvant treatment and radiation therapy in accordance with national guidelines. Recurrence-free survival was analyzed in the per-protocol population. Noninferiority of sentinel node biopsy only was shown if the upper boundary of the confidence interval for the hazard ratio was below 1.44.
Key Findings
Median follow-up was 46.8 months (range = 1.5–94.5 months). Among patients who remained enrolled in the trial for at least 1 year, 1,192 (89.9%) of 1,326 in the sentinel node biopsy group and 1,058 (88.4%) of 1,197 in the axillary dissection group underwent postoperative radiation therapy targeting regional nodes.
Estimated 5-year recurrence-free survival was 89.7% (95% confidence interval [CI] = 87.5%–91.9%) in the sentinel node biopsy group vs 88.7% (95% CI = 86.3%–91.1%) in the axillary dissection group; the country-adjusted hazard ratio was 0.89 (95% CI = 0.66–1.19), which was significantly (P < .001) below the prespecified noninferiority margin.
For the sentinel node biopsy group vs the axillary dissection group, estimated 5-year overall survival was 92.9% (95% CI = 91.0%–94.9%) vs 92.0% (95% CI = 89.9%–94.1%). Estimated 5-year breast cancer–specific survival was 97.1% (95% CI = 95.8%–98.3%) vs 96.6% (95% CI = 95.3%–97.9%).
The investigators concluded, “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.”
Jana de Boniface, MD, PhD, of the Department of Surgery, Capio St. Goran’s Hospital, Stockholm, is the corresponding author for The New England Journal of Medicine article.
Disclosure: The study was funded by the Swedish Research Council and others. For full disclosures of the study authors, visit nejm.org.
