Testing the Role of FDG-PET/CT to Predict Response to Therapy Prior to Surgery for HER2-positive Breast Cancer, The DIRECT Trial

Inclusion Criteria: * Patients (all genders) must be \>= 18 years of age. * Patient must have the ability to understand and the willingness to sign a written informed consent document. Patients with impaired decision-making capacity (IDMC) who have a legally authorized representative (LAR) or caregiver and/or family member available will also be considered eligible. * Patient must have an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2. * Patient must have histologically confirmed HER2-positive primary invasive breast carcinoma by American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guidelines that has been determined by local testing. * Patient must have known (either positive or negative) hormone receptor (estrogen receptor \[ER\] or progesterone receptor \[PR\]) status by local testing, per ASCO/CAP guidelines. Patients with either hormone receptor-positive or hormone receptor- negative HER2-positive breast cancer are eligible. * Patient must have American Joint Committee on Cancer (AJCC) 8th Edition stage IIa-IIIc according to anatomic staging table at diagnosis and below criteria. * Patients without nodal involvement (cN0) are eligible if T size \> 2.0 cm (T2-4) * Patients with nodal involvement (cN1-3) are eligible if T2-4 * Patients with clinical T4d are not eligible * Patients with bilateral invasive breast cancers are eligible if both cancers are HER2-positive and at least one meets all protocol eligibility c…