POSNOC - A Trial Looking at Axillary Treatment in Early Breast Cancer

Inclusion Criteria: * Unifocal or multi-focal invasive tumour with lesion ≤5 cm in its largest dimension, measured pathologically or largest invasive tumour diameter on radiology should be used for women who are randomised intra-operatively or undergo sentinel node biopsy before neoadjuvant therapy (tumour size should be based only on the single largest tumour; do not add the sizes together from the multiple foci) * At sentinel node biopsy have 1 or 2 nodes with macrometastases (tumour deposit \>2.0mm in largest dimension or defined as macrometastasis on molecular assay) * Fit for axillary treatment and adjuvant therapy * Have given written informed consent Exclusion Criteria: * bilateral invasive breast cancer * more than 2 nodes with macrometastases * neoadjuvant therapy for breast cancer except: * if sentinel node biopsy performed prior to neoadjuvant chemotherapy in women with early breast cancer * short duration of neoadjuvant endocrine therapy is acceptable (up to 3 months) * previous axillary surgery on the same body side as the scheduled sentinel node biopsy * not receiving adjuvant systemic therapy * previous cancer less than 5 years previously or concomitant malignancy except: * basal or squamous cell carcinoma of the skin * in situ carcinoma of the cervix * in situ melanoma * contra- or ipsilateral in situ breast cancer