Randomized trial of axillary surgery as part of breast-conserving therapy in breast cancer

Whether surgical axillary staging as part of breast-conserving therapy (BCT) can be omitted without compromising survival is currently unclear. The prospective INSEMA trial in Germany, Austria, and Switzerland included patients with clinically node-negative invasive T1 or T2 breast cancer who were scheduled to undergo BCT. Patients were randomized to undergo treatment without axillary surgery (surgery-omission group) or sentinel-lymph-node biopsy (surgery group). Primary end point was invasive disease-free survival (IDFS) rate at 5 years in the per-protocol population. The median follow-up was 73.6 months. Five-year IDFS rate was 91.9% in the surgery-omission group and 91.7% in the surgery group (HR 0.91; 95% CI 0.73-0.14) indicating noninferiority of omission of surgery. Invasive disease and death from any cause were seen in 1.0% and 1.4%, respectively, in the surgery-omission group, and 0.3% and 2.4%, respectively, in the surgery group. Patients in the surgery-omission group had a lower incidence of lymphedema, greater arm mobility, and less pain with movement of the arm or shoulder than patients in the surgery group. The authors conclude that among patients with clinically node-negative, T1 or T2 invasive breast cancer, omission of surgical axillary staging was noniferior to SLNB after a median follow-up of 6 years.