INSEMA
Trial question
Is omission of axillary surgery noninferior to sentinel lymph node biopsy in patients with clinically node-negative, T1 or T2 invasive breast cancer?
Study design
Multi-center
Open label
RCT
Population
4858 female patients.
Inclusion criteria: patients with clinically node-negative, T1 or T2 invasive breast cancer.
Key exclusion criteria: history of malignancy in the past 5 years; time since core biopsy > 3 months; invasive breast carcinoma treated with neoadjuvant therapy; histologically noninvasive breast carcinoma; planned total mastectomy; planned intraoperative radiotherapy or postoperative partial breast irradiation; pregnancy or lactation; male patients.
Interventions
N=962 surgery omission (no axillary surgery in cases with newly diagnosed breast cancer and clinically negative axillary status).
N=3896 sentinel lymph node biopsy (sentinel lymph node biopsy in cases with newly diagnosed breast cancer and clinically negative axillary status).
Primary outcome
Invasive disease-free survival at 5 years
91.9%
91.7%
91.9 %
68.9 %
46.0 %
23.0 %
0.0 %
Surgery
omission
Sentinel lymph node
biopsy
Difference not exceeding
non-inferiority
margin ✓
Difference not exceeding non-inferiority margin in invasive disease-free survival at 5 years (91.9% vs. 91.7%; HR 1.1, 95% CI 0.88 to 1.37).
Secondary outcomes
No significant difference in overall survival at 5 years (98.2% vs. 96.9%; HR 1.45, 95% CI 0.98 to 2.17).
Safety outcomes
Significant differences in lymphedema (1.8% vs. 5.7%), restriction of arm or shoulder mobility (2.0% vs. 3.5%), pain with arm or shoulder movement (2.0% vs. 4.2%).
Conclusion
In patients with clinically node-negative, T1 or T2 invasive breast cancer, surgery omission was noninferior to sentinel lymph node biopsy with respect to invasive disease-free survival at 5 years.
Reference
Toralf Reimer, Angrit Stachs, Kristina Veselinovic et al. Axillary Surgery in Breast Cancer - Primary Results of the INSEMA Trial. N Engl J Med. 2025 Mar 13;392(11):1051-1064.
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