Pragmatic Randomized Trial of Proton vs. Photon Therapy for Patients With Non-Metastatic Breast Cancer: A Radiotherapy Comparative Effectiveness (RADCOMP) Consortium Trial

Inclusion Criteria: * Females or males diagnosed with pathologically (histologically) proven invasive mammary carcinoma (ductal, lobular or other) of the breast who have undergone either mastectomy or lumpectomy with any type of axillary surgery or axillary sampling. * For patients who have undergone lumpectomy, any type of mastectomy and any type of reconstruction (including no reconstruction) are allowed. * For patients who have undergone lumpectomy, there are no breast size limitations. * Patients with non-metastatic breast cancer are eligible. This includes American Joint Committee on Cancer (AJCC) 7th edition left- or right-sided breast cancer clinical or pathologic stage I, II, III or loco-regionally recurrent at time of diagnosis. For patients that receive neoadjuvant chemotherapy, AJCC 7th edition left- or right-sided breast cancer pathologic stage yp 0, I, II, III are eligible. * Bilateral breast cancer is permitted. Patients with bilateral breast cancer will be stratified as left-sided. * Must be proceeding with breast/chest wall and nodal radiation therapy including internal mammary node treatment. * Must have a pertinent history/physical examination within 90 days prior to registration. * Age ≥ 21 years * ECOG Performance Status 0 - 2 (asymptomatic to symptomatic but capable of self-care) within 90 days prior to randomization. * Confirmation that the patient's health insurance will pay for the treatment in this study (patients may still be responsible for some co…