-  Female. Men are excluded from this study because the number of men with breast cancer
             is insufficient to provide a statistical basis for assessment of effects in this
             subpopulation of people with breast cancer.

          -  Pathologically confirmed diagnosis of breast cancer, clinical stage I-II (T1-3 N0 M0,
             T0-2 N1 M0). Diagnosis must be by needle biopsy; patients diagnosed by surgical
             excision are excluded.

          -  Patients must have either:

               -  Estrogen receptor (ER) negative/progesterone receptor (PR) negative (< 10% by
                  immunohistochemistry IHC staining) and HER-2 negative breast cancer OR

               -  ER negative/PR negative (< 10% by IHC staining) and HER-2 positive tumors

               -  HER-2 status will be determined as per the 2013 ASCO CAP guidelines:

                    -  HER-2 is considered positive if there is IHC 3+ staining or ISH positive
                       using either single probe ISH or dual probe ISH

                    -  HER-2 is considered negative if there is IHC 0 or 1+ staining or ISH
                       negative using either single probe ISH or dual probe ISH

          -  No patients with previous ipsilateral invasive breast cancer or ductal carcinoma in
             situ (DCIS)

          -  No patients with bilateral breast cancer

          -  No patients with known deleterious mutations in breast cancer (BRCA) genes

          -  No current history of receiving hormonal therapy, tamoxifen, and or aromatase
             inhibitors for therapeutic measures

          -  No history of chemotherapy for cancer within 6 months prior to registration

          -  No patients scheduled to receive neoadjuvant chemotherapy or partial breast
             irradiation following breast conserving surgery

          -  Eligible for BCT based on clinical examination, mammography and, if standard practice
             at a given institution, ultrasound and/or tomogram. Women who cannot be appropriately
             selected for BCT based on these standard imaging studies, and for whom additional
             imaging is recommended to clarify local disease extent, will not be eligible for this
             trial.

          -  No patients with multicentric or multifocal disease scheduled to undergo multiple
             lumpectomies. Multifocal disease that can be encompassed in a single operative bed can
             be enrolled.

          -  Suitable to undergo MRI and receive the contrast agent gadolinium (exclusions follow):

               -  No history of untreatable claustrophobia

               -  No presence of metallic objects or implanted medical devices in body (i.e.,
                  cardiac pacemaker, aneurysm clips, surgical clips, prostheses, artificial hearts,
                  valves with steel parts, metal fragments, shrapnel, tattoos near the eye, or
                  steel implants)

               -  No history of sickle cell disease

               -  No contraindication to intravenous contrast administration

               -  No known allergy-like reaction to gadolinium or moderate or severe allergic
                  reactions to one or more allergens as defined by the American College of
                  Radiology (ACR); patient may be eligible if willing to undergo pre-treatment as
                  defined by the institution's policy and/or ACR guidance

               -  No findings consistent with renal failure, as determined by glomerular filtration
                  rate (GFR) < 30 mL/min/1.73 m^2 based on a creatinine level obtained within 28
                  days prior to registration

               -  Weight lower than that allowable by the MRI table

          -  No prior MRI of study breast within the 12 months prior to registration

          -  Non-pregnant and non-lactating. Patients of child-bearing potential must have a
             negative pregnancy test within 7 days prior to registration. Perimenopausal patients
             must be amenorrheic > 12 months to be considered not of child-bearing potential

          -  ≥ 18 years of age

          -  Signed study-specific informed consent prior to registration