{"entity":{"id":"atnec","kind":"trial","name":"ATNEC","aka":["Axillary management in breast cancer patients with needle biopsy proven nodal metastases after neoadjuvant chemotherapy"],"tldr":"If chemotherapy has cleared the lymph nodes completely, does the armpit still need an operation or radiotherapy? This British trial is asking, with arm swelling counted as an equal endpoint to survival. It is still recruiting.","summary":"ATNEC opened on 26 February 2021 and is recruiting towards an estimated 1,900 participants, with an estimated primary completion of February 2030. Patients whose nodal disease was proven by needle biopsy at diagnosis and whose sentinel node biopsy after chemotherapy shows no residual cancer are randomised to no further axillary treatment or to axillary treatment, which is either clearance or radiotherapy.\n\nThe design says something about how the field has changed. Disease-free survival and patient-reported lymphoedema are co-primary outcomes, not primary and secondary: the trial is built to fail if the de-escalation is safe but the two arms cannot be separated on arm morbidity, and to succeed on the same footing if it spares arms. Funding is from the National Institute for Health and Care Research under reference NIHR 128311.\n\nATNEC sits alongside NSABP B-51, which asked the radiotherapy half of the same question and found that regional nodal irradiation adds nothing when the nodes clear. No ATNEC results have been published and none are quoted here.","status":"recruiting","asOf":"2026-09-25","links":[{"label":"ClinicalTrials.gov NCT04109079","url":"https://clinicaltrials.gov/study/NCT04109079"}],"tags":[],"related":[],"cancers":["breast-cancer","breast-hr-positive","breast-her2-positive","tnbc"],"sections":[],"technologies":["sentinel-node"],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":["targeted-axillary-dissection","sentinel-lymph-node-biopsy","axillary-surgery-de-escalation","breast-cancer-related-lymphoedema","neoadjuvant-versus-adjuvant-breast"],"trials":["acosog-z1071","targeted-axillary-dissection-md-anderson","nsabp-b51","posnoc"],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"nct":"NCT04109079","phase":"3","setting":"Breast cancer with nodal metastases proven by needle biopsy at diagnosis, and no residual nodal cancer on sentinel node biopsy after chemotherapy: no further axillary treatment against axillary clearance or axillary radiotherapy, with disease-free survival and patient-reported lymphoedema at five years as co-primary outcomes","sponsor":"University Hospitals of Derby and Burton NHS Foundation Trust, funded by the National Institute for Health and Care Research","enrolled":1900,"enrolledBasis":"registry","outcomes":[]},"route":"/trials/atnec/","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":"neoadjuvant-versus-adjuvant-breast","kind":"term","name":"Drugs before or after the operation","route":"/terms/neoadjuvant-versus-adjuvant-breast/"},{"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/"},{"id":"targeted-axillary-dissection","kind":"term","name":"Targeted axillary dissection","route":"/terms/targeted-axillary-dissection/"}],"trial":[{"id":"acosog-z1071","kind":"trial","name":"ACOSOG Z1071 (Alliance)","route":"/trials/acosog-z1071/"},{"id":"nsabp-b51","kind":"trial","name":"NSABP B-51 / RTOG 1304","route":"/trials/nsabp-b51/"},{"id":"posnoc","kind":"trial","name":"POSNOC","route":"/trials/posnoc/"},{"id":"targeted-axillary-dissection-md-anderson","kind":"trial","name":"Targeted axillary dissection (MD Anderson prospective study)","route":"/trials/targeted-axillary-dissection-md-anderson/"}]}}