Magnetic resonance imaging (MRI) for assessment of axillary lymph node metastases in breast cancer: systematic review

INTRODUCTION Assessment of axillary lymph node status is important in breast cancer staging. UK guidance recommends sentinel lymph node biopsy (SLNB) or 4-node sampling (4-NS) where ultrasound and ultrasound-guided biopsy are negative. Where biopsy, SLNB or 4-NS are positive, axillary lymph node dissection (ALND) is recommended. The surgical procedure ALND, and to a lesser extent SLNB and 4-NS, are associated with adverse effects such as arm lymphoedema. Magnetic resonance imaging (MRI) provides detailed images of the body in any plane and is a non-invasive technique with few adverse events. An MRI scan may provide information on whether a lymph node is suspicious for metastasis, avoiding the need for surgery and its associated adverse effects. However, it is unclear whether MRI can match the excellent diagnostic accuracies of ALND, SLNB and 4-NS.