Omission of Surgery and Sentinel Lymph Node Dissection in Clinically Low-risk HER2positive Breast Cancer With High HER2 Addiction and a Complete Response Following Standard Anti- HER2-based Neoadjuvant Therapy (ELPIS Trial)

Pertuzumab and trastuzumab FDC subcutaneous, A loading dose of 1200 mg pertuzumab and 600 mg trastuzumab followed by a maintenance dose of 600 mg pertuzumab and 600 mg; day 1 of each 3 week cycle during 5 neoadjuvant cycles and 13 adjuvant cycles if complete response

80 mg/m2, day 1,8,15 of each 3 week cycle during 4 cycles

3,6 mg/kg, 14 adjuvant cycles if not complete response

Adjuvant endocrine therapy will be administered as per local practice and according to recognized clinical practice guidelines

Omission of surgery and sentinel lymph node dissection in patients with HER2-E and ERBB2 high breast cancer who achieving a complete response following standard anti-HER2-based neoadjuvant therapy with paclitaxel/trastuzumab/pertuzumab