Preoperative Accelerated Partial Breast Irradiation for Triple Negative Breast Cancer Using Proton Beam Scanning

Inclusion Criteria:

Age at least 40 years
Core biopsy proven estrogen negative (< 1%), progesterone negative (< 1%), and HER2-neu negative (+1 by immunohistochemistry and/or FISH ratio < 2.0) invasive breast cancer
Unicentric AJCC 7th edition T1N0M0 tumor measuring no greater than 2.0 cm in longest dimension on initial imaging with either breast MRI and/or mammogram
ECOG Performance status < 1
No prior treatment for this diagnosis of cancer
No prior radiation to the ipsilateral breast, a history of contralateral breast radiation is permitted
No clinical or radiographic evidence of malignant regional adenopathy
No contraindication to breast conserving surgery, sentinel lymph node biopsy, or radiation therapy
Ability to understand and willingness to sign a written informed consent document.
Pregnant females are excluded. Female subjects of childbearing potential must indicate to their physician that there is not a possibility of being pregnant at the time of enrollment or have a negative pregnancy test prior to initiation of radiation therapy

Exclusion Criteria:

Multicentric breast cancer, defined as discontiguous tumors separated by at least 5 cm of uninvolved tissue or discontiguous tumors that are located within separate breast quadrants either clinical or mammographically.
Multifocal breast cancer, defined as discontiguous discrete foci of invasive carcinoma, separated by uninvolved intervening tissue, but within an overall span of 5 cm, or within the same breast quadrant.
Tumor > 2.0 cm, nodal involvement, or metastatic involvement
Patients with either diffuse (>1 quadrant or > 5 cm) suspicious microcalcifications on mammogram or diffuse non-mass-like enhancement on MRI
History of ipsilateral cosmetic or reconstructive breast surgery
Patients with a pacemaker or defibrillator
Any contraindication to MRI including but not limited to the presence of a pacemaker/defibrillator or other implanted ferromagnetic device or an inability to lie prone
Pregnant or lactating women
Medical condition including but not limited to ongoing or active infection or connective tissue disease (e.g. systemic sclerosis or other collagen vascular diseases) that would, in the opinion of the treating physician, make this protocol unreasonably hazardous to the patient.
Psychiatric illness/social situation that would limit ability to provide informed consent