Evaluating 6-months of HER2-targeted Therapy in Patients With HER2 Positive Early-stage Breast Cancer That Achieve a Pathological Complete Response to Neoadjuvant Systemic Therapy

Patients with early-stage HER2-positive breast cancer who demonstrate a pathological complete response at time of surgery will be treated with HER2 targeted therapy for a total of 9 treatments every 3 weeks (or its equivalent if given weekly) including the treatment received preoperatively.