ATNEC: Axillary management in T1-3N1M0 breast cancer patients with needle biopsy proven nodal metastases at presentation after neoadjuvant chemotherapy

ATNEC is a phase III, open, randomised, multicentre trial comparing standard axillary treatment (either, axillary lymph node dissection [ALND] or axillary radiotherapy [ART]) with no axillary treatment post-surgery, in early stage (T1-3N1M0) breast cancer patients.

Currently, the presence of axillary lymph node metastases on needle biopsy, prior to neoadjuvant chemotherapy, is the determinant for whether a patient requires further axillary treatment (ALND or ART) post-surgery.
Axillary treatment damages lymphatic drainage from the arm and can cause life-long side effects such as lymphoedema, restricted shoulder movement or discomfort, pain, sensory changes and numbness. These adverse events interfere with daily activities, impair quality of life and are costly to the NHS in terms of rehabilitative treatments.

As more effective neoadjuvant chemotherapy is now available, that results in complete eradication of cancer in the axilla in 40% to 70% of patients, extensive axillary treatment may no longer be necessary in patients with no evidence of residual nodal disease. The ATNEC study aims to address this question.