INSEMA
Can axillary staging surgery be omitted in selected clinically node-negative early breast cancer without compromising invasive DFS?
One underlying study; aliases and follow-up reports consolidated. Primary discipline: Surgical.
5,502 eligible patients with clinically node-negative T1–T2 breast cancer planned for breast-conserving surgery; per-protocol population n=4,858.
Clinically node-negative T1–T2 disease ≤5 cm undergoing breast-conserving surgery; do not extrapolate automatically to mastectomy or neoadjuvant settings.
5,502 randomised; per-protocol 4,858 randomised/evaluable as reported.
Breast-conserving surgery without axillary surgery.
Breast-conserving surgery plus sentinel lymph-node biopsy.
Endpoints and results
Primary 5-year invasive DFS; axillary recurrence and arm morbidity secondary.
- Median follow-up 73.6 months.
- 5-year invasive DFS 91.9% vs 91.7%; HR 0.91 (95% CI 0.73–1.14), below prespecified non-inferiority margin 1.271.
- Axillary recurrence 1.0% vs 0.3%; omission reduced lymphedema and arm/shoulder symptoms.
Absolute Effect and outcome visualisation
5-year invasive DFS
% invasive disease-free at 5 years · 5 years. Bars show source-reported fixed-time percentages.
Interpretation: Non-inferiority, not superiority. No benefit NNT from the 0.2-point numerical difference; show 0.7-point higher axillary recurrence alongside reduced morbidity.
Toxicity, discontinuation and quality of life
Trial-specific harms: Less lymphedema, better arm mobility and less pain with omission; axillary recurrence 1.0% vs 0.3%.
Treatment burden/discontinuation: Avoids an additional axillary procedure and recovery.
Quality of life: Arm mobility and pain outcomes favoured omission; exact PRO instrument/timepoint estimates should be drawn from the full report.
Subgroups, maturity and limitations
Subgroups: Most patients had T1 tumours; apply only to the studied breast-conserving population.
Maturity: Median follow-up 73.6 months.
Limitations: Per-protocol non-inferiority design; do not conflate with ACOSOG Z0011, which studied completion dissection after positive sentinel nodes.
INSEMA supports omission of axillary staging in carefully selected clinically node-negative patients undergoing breast-conserving surgery.
Use current regional guidelines, patient fitness, biomarkers, competing risks, alternatives and regulatory status before clinical application. Clinical freshness review and browser-rendered QA remain pending.
Primary sources and registry
Registry: NCT02466737
The Absolute Effect · Updated 26 October 2026 · Never derive NNT from median survival.