{"entity":{"id":"insema","kind":"trial","name":"INSEMA (Intergroup Sentinel Mamma)","aka":["Intergroup Sentinel Mamma"],"tldr":"The largest trial of skipping the armpit operation, and the one with six years of follow-up. Women who had no lymph node surgery did as well as those who did, and had less arm swelling, better shoulder movement and less pain.","summary":"INSEMA randomised 5,502 eligible patients in a 1:4 ratio to no axillary surgery or to sentinel lymph node biopsy. All had clinically node-negative T1 or T2 invasive breast cancer and were scheduled for breast-conserving surgery; 90 percent had clinical T1 disease and 79 percent pathological T1 disease. The per-protocol population was 4,858, of whom 962 had no axillary surgery.\n\nAt a median follow-up of 73.6 months, the estimated five-year invasive disease-free survival was 91.9 percent (95 percent confidence interval 89.9 to 93.5) without axillary surgery and 91.7 percent (90.8 to 92.6) with sentinel node biopsy, a hazard ratio of 0.91 (0.73 to 1.14), below the non-inferiority margin of 1.271. Of the 525 first primary-outcome events, the apparent differences were in axillary recurrence, 1.0 percent without surgery against 0.3 percent with it, and in death, 1.4 against 2.4 percent. Patients who had no axillary surgery had less lymphoedema, greater arm mobility and less pain on moving the arm or shoulder.\n\nThe axillary recurrence figures are the number to hold on to: omitting the operation roughly triples a very small risk, from three in a thousand to ten in a thousand at five years, and does not change how long women live. Whether the same holds for invasive lobular carcinoma is disputed: a single-institution series found high rates of occult nodal positivity in lobular tumours meeting INSEMA and SOUND criteria.","status":"positive","asOf":"2026-09-25","links":[{"label":"ClinicalTrials.gov NCT02466737","url":"https://clinicaltrials.gov/study/NCT02466737"},{"label":"INSEMA primary results (New England Journal of Medicine 2025)","url":"https://doi.org/10.1056/NEJMoa2412063"}],"tags":[],"related":[],"cancers":["breast-cancer","breast-hr-positive","breast-her2-positive","tnbc"],"sections":[],"technologies":["sentinel-node"],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":["sentinel-lymph-node-biopsy","axillary-surgery-de-escalation","breast-cancer-related-lymphoedema"],"trials":["sound","nsabp-b32"],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"nct":"NCT02466737","phase":"3","setting":"Clinically node-negative T1 or T2 invasive breast cancer scheduled for breast-conserving surgery: no axillary surgery against sentinel node biopsy, with five-year invasive disease-free survival as the primary endpoint and a non-inferiority margin of 1.271","sponsor":"University of Rostock, funded by German Cancer Aid","result":"Five-year invasive disease-free survival 91.9 percent without axillary surgery against 91.7 percent with sentinel node biopsy (hazard ratio 0.91, 0.73 to 1.14, non-inferior); axillary recurrence 1.0 against 0.3 percent.","yearReported":2025,"enrolled":5502,"enrolledBasis":"randomised","enrolledNote":"5,502 eligible patients were randomised in a 1:4 ratio and 4,858 were in the per-protocol population; the ClinicalTrials.gov record NCT02466737 gives 5,505.","outcomes":[{"endpoint":"Invasive disease-free survival at 5 years","primary":true,"unit":"%","arms":[{"name":"No axillary surgery","n":962,"value":91.9,"note":"95 percent confidence interval 89.9 to 93.5"},{"name":"Sentinel lymph node biopsy","n":3896,"value":91.7,"note":"95 percent confidence interval 90.8 to 92.6"}],"hr":0.91,"ci":[0.73,1.14],"source":"https://doi.org/10.1056/NEJMoa2412063"},{"endpoint":"Axillary recurrence as a first primary-outcome event","unit":"%","arms":[{"name":"No axillary surgery","n":962,"value":1},{"name":"Sentinel lymph node biopsy","n":3896,"value":0.3}],"source":"https://doi.org/10.1056/NEJMoa2412063"}],"replication":"SOUND reached the same conclusion in 1,405 patients with tumours up to 2 cm and a negative axillary ultrasound."},"route":"/trials/insema/","neighbours":{"cancer":[{"id":"breast-cancer","kind":"cancer","name":"Breast cancer (all types)","route":"/cancers/breast-cancer/"},{"id":"breast-her2-positive","kind":"cancer","name":"HER2-positive breast cancer","route":"/cancers/breast-her2-positive/"},{"id":"breast-hr-positive","kind":"cancer","name":"HR-positive / HER2-negative breast cancer","route":"/cancers/breast-hr-positive/"},{"id":"tnbc","kind":"cancer","name":"Triple-negative breast cancer (TNBC)","route":"/cancers/tnbc/"}],"technology":[{"id":"sentinel-node","kind":"technology","name":"Sentinel lymph node biopsy","route":"/technologies/sentinel-node/"}],"term":[{"id":"axillary-surgery-de-escalation","kind":"term","name":"Doing less to the armpit","route":"/terms/axillary-surgery-de-escalation/"},{"id":"breast-cancer-related-lymphoedema","kind":"term","name":"Lymphoedema after breast cancer treatment","route":"/terms/breast-cancer-related-lymphoedema/"},{"id":"sentinel-lymph-node-biopsy","kind":"term","name":"Sentinel node biopsy","route":"/terms/sentinel-lymph-node-biopsy/"}],"trial":[{"id":"nsabp-b32","kind":"trial","name":"NSABP B-32","route":"/trials/nsabp-b32/"},{"id":"sound","kind":"trial","name":"SOUND (Sentinel Node vs Observation After Axillary Ultra-Sound)","route":"/trials/sound/"}]}}