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: E-poster/poster
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)
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.
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.
Funder: NIHR HTA
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.