Breast cancer
Current interventions as of 19/07/2023: ATNEC is a multi-centre, randomised clinical trial with a non-inferiority endpoint and a pragmatic design. ATNEC will be conducted in patients with early-stage, node-positive breast cancer, whose usual treatment pathway would be neoadjuvant chemotherapy followed by breast surgery and further treatment to the armpit (lymph node clearance or radiotherapy to the armpit). Patients who have no residual cancer in the lymph glands after chemotherapy will be randomised to either have standard armpit treatment or no further treatment to the armpit. An integrated feasibility study, with embedded qualitative research, will assess the willingness of clinicians and patients to participate in the ATNEC trial. Pre-Randomisation: To be eligible, a patient must be diagnosed with early-stage, confirmed node-positive breast cancer on needle biopsy, and planned to receive chemotherapy first (neoadjuvant chemotherapy) prior to surgery. The patient’s primary tumour must have been evaluated for receptor status. Patients can be either female or male, and must be aged 18 years or older. Patients who are confirmed to be eligible will be invited to take part in the study and if, following review of the patient information sheet, they decide to participate, written informed consent will be obtained. Once a patient has consented to participate, the site team will be able to register them to the study via the ATNEC online registration portal. The patient will be assigned a unique trial number, which will be used to identify them throughout the study. It is recommended that the patient’s clinical team will mark the abnormal armpit lymph gland – this could be done either by using a clip, carbon dye or by inserting a magnetic seed as per local practice. Patients will then continue to receive neo-adjuvant chemotherapy, as per standard practice. Following the completion of their chemotherapy, patients will undergo imaging assessment of the lymph glands
Current key inclusion criteria as of 16/03/2026: 1. Age ≥ 18 years 2. Male or female 3. cT1-3N1M0 breast cancer at diagnosis (prior to NACT) as per AJCC 8th edition 3.1. Patients with occult primary invasive breast cancer (no identifiable invasive cancer in the breast) with FNA or core biopsy proven nodal metastases are eligible for the study. 4. FNA or core biopsy confirmed axillary nodal metastases at presentation 5. Oestrogen receptor and HER2 status evaluated on primary tumour 6. Received standard NACT as per local guidelines (Patients undergoing neoadjuvant endocrine therapy as part of another clinical trial are eligible) 7. Imaging of the axilla, as required, to assess response to NACT (per local guidelines) 8. Undergo a dual tracer sentinel node biopsy (SNB) after NACT with at least 3 nodes removed. 8.1. If a single tracer SNB is performed: the patient is eligible only if the involved node is marked before or during NACT, and at least 3 nodes (including the marked node) are removed during sentinel node biopsy. 8.2. If the node is not marked or the marked node is not removed: the patient is eligible only if the histology report shows evidence of down-staging with complete pathological response e.g., fibrosis or scarring in at least one node and at least 3 nodes removed. 8.3. If fewer than 3 nodes are found on histology: the patient is eligible only if BOTH points a) and b), below, are met: a) involved node was marked and removed during SNB; and b) removed marked node shows evidence of downstaging on histology e.g. fibrosis or scarring. 9. If the sentinel node(s) cannot be localised on SNB: axillary node sampling should be performed, the patient will be eligible if at least 3 nodes are removed. 10. No evidence of nodal metastases post NACT (isolated tumour cells, micro or macro metastasis) 11. Patients with complete pathological response in the axilla but residual disease in the breast post NACT are eligible for the study 12. Patients who are cN0 (node negati
Current key exclusion criteria as of 16/03/2026: 1. Bilateral synchronous invasive breast cancer 2. Sentinel node biopsy prior to NACT 3. Previous axillary nodal surgery on the same body side as the scheduled targeted sampling 4. Any previous cancer within last 5 years or concomitant malignancy except 4.1. basal or squamous cell carcinoma of the skin 4.2. in situ carcinoma of the cervix 4.3. in situ or stage 1 melanoma 4.4. contra- or ipsilateral in situ breast cancer 4.5. chronic lymphocytic leukaemia not on treatment _____ Previous exclusion criteria as of 19/07/2023: 1. Bilateral synchronous invasive breast cancer 2. Sentinel node biopsy prior to NACT 3. Previous axillary surgery on the same body side as the scheduled targeted sampling 4. Any previous cancer within 5 years or concomitant malignancy except: 4.1. Basal or squamous cell carcinoma of the skin 4.2. In situ carcinoma of the cervix 4.3. In situ melanoma 4.4. Contra- or ipsilateral in situ breast cancer _____ Previous exclusion criteria: 1. Bilateral invasive breast cancer 2. Sentinel node biopsy prior to NACT 3. Marked node not removed except where the node/s removed show evidence of down-staging with complete pathological response e.g. fibrosis or scarring 4. Previous axillary surgery on the same body side as the scheduled targeted sampling 5. Any previous cancer within 5 years or concomitant malignancy except: 5.1. Basal or squamous cell carcinoma of the skin 5.2. In situ carcinoma of the cervix 5.3. In situ melanoma 5.4. Contra- or ipsilateral in situ breast cancer