Omission of Surgery in Clinically Low-risk HER2positive Breast Cancer With High HER2 Addiction and a Complete Response Following Standard Anti-HER2-based Neoadjuvant Therapy

After 13 weeks of neoadjuvant treatment, a breast MRI will be performed. If a complete response is observed on breast MRI, patients will undergo a stereotactic-guided VAB of the marker area to obtain 12 cylinders of breast parenchyma, which is equivalent to 2 grams of tissue. If no invasive tumor cells and no in situ disease are identified in the stereotactic-guided VAB, patients will be eligible to omit loco-regional surgery.