ATNEC: A multicentre, randomised trial investigating whether axillary treatment can be avoided in patients with no residual cancer in the lymph glands after neoadjuvant chemotherapy


Session type:

Amit Goyal1, Janet Dunn2, Sophie Cramp2, Andrea Marshall2, Duncan Wheatley3, Natalie Hammonds2, Shama Puri1, Tara Homer4, Luke Vale4, Romaana Mir5, Janice Rose6, Helen Teresa Edwards7, Samreen Ahmed8, Abeer Shaaban9, Beatrix Elsberger10, Julie Bruce2, Sophie Gasson2, Valerie Speirs11, Jacqui Shaw12, Helen Higgins2
1University Hospitals of Derby and Burton NHS Foundation Trust, 2University of Warwick, 3Royal Cornwall Hospitals NHS Trust, 4Newcastle University, 5Mount Vernon Cancer Centre, 6National Cancer Research Institute (NCRI), 7Independent Cancer Patients’ Voice (ICPV), 8University Hospitals of Leicester NHS Trust, 9University Hospitals Birmingham NHS Foundation Trust, 10NHS Grampian – Aberdeen Royal Infirmary, 11University of Aberdeen, 12University of Leicester



For patients who are node positive at presentation, and are found to have a complete nodal tumour response (ypN0) post-neoadjuvant chemotherapy (NACT), it is not yet known whether local axillary therapy can be modified based on the response to NACT. ATNEC specifically addresses axillary management following NACT, in patients with proven axillary node metastases.


Design: ATNEC is a phase III, randomised (1:1) trial. Patients with proven axillary node metastases on needle biopsy receive NACT followed by sentinel node biopsy (SNB). Patients whose sentinel nodes have converted to benign (ypN0) on SNB will be randomised to receive either axillary treatment (nodal radiotherapy or axillary nodal clearance) vs. no axillary treatment (without further surgery).

Stratification: Institution, type of breast surgery (breast conserving surgery/ mastectomy), receptor status (triple negative, HER2 positive, ER positive and/or PR positive and HER2 negative)

Inclusion criteria:

  • ≥ 18
  • Male or female
  • T1-3N1M0 breast cancer at diagnosis (pre-NACT)
  • FNA or core biopsy confirmed axillary nodal metastases at presentation
  • ER and HER2 status evaluated on primary tumour
  • Received standard NACT, per local guidelines
  • Imaging of the axilla post-NACT
  • SNB post-NACT and at least 3 nodes removed (sentinel nodes and marked node).
  • No evidence of nodal metastases post-NACT (ypN0)
  • Written informed consent

Exclusion criteria:

  • Bilateral invasive breast cancer
  • SNB pre-NACT
  • Marked node not removed except where ≥1 node removed shows down-staging with complete pathological response
  • Previous ipsilateral axillary nodal surgery
  • Previous cancer within 5 years or concomitant malignancy


Outcomes: The primary outcomes are disease free survival (DFS), and the risk of lymphoedema at five years.


Radiotherapy Quality Assurance: ATNEC has an in-built radiotherapy QA programme coordinated by the national Radiotherapy Trials QA (RTTQA) group, to ensure consistent radiotherapy practice.


Status: Recruiting


Target accrual: 1900 to assess a 3.5% non-inferiority margin with 5% 1-sided significance and 85% power for DFS and a 5% difference in lymphoedema with 5% 2-sided significance level and 90% power.


Sites: 100

Funder: NIHR HTA



Impact statement

ATNEC will give us a more definitive answer to the longer-term safety of sentinel node biopsy post-neoadjuvant chemotherapy and whether we can modify local axillary therapy based on the response to neoadjuvant chemotherapy.