Intensity Modulated Accelerated Partial Breast Irradiation in Treating Older Patients with Hormone Responsive Stage 0-I Breast Cancer before Surgery

Inclusion Criteria

• COHORT I:
• The patient must consent to be in the study and must have signed an approved consent form conforming with federal and institutional guidelines
• Patient must be > 18 years
• The patient must have clinical node negative, stage I breast cancer
• The surgical treatment must be intended to be a lumpectomy
• The biopsy site must have been demarcated by a clip(s)
• Gross disease must be unifocal on mammogram (mammo)/magnetic resonance imaging (MRI) imaging
• Patient must be able to tolerate lying in the prone position with arms extended forward
• Must be able to tolerate MRI scan with contrast
• COHORT II: The patient must consent to be in the study and must have signed an approved consent form conforming with federal and institutional guidelines
• COHORT II: Patient must be >= 50 years
• COHORT II: Core biopsy demonstrating breast cancer and receptors that are estrogen receptor (ER) or progesterone receptor (PR) positive
• COHORT II: Core tissue must have human epidermal growth factor receptor 2 (HER 2) testing
• COHORT II: The patient must have clinical node negative, stage I breast cancer
• COHORT II: The surgical treatment must be intended to be a lumpectomy
• COHORT II: The biopsy site must have been demarcated by a clip(s)
• COHORT II: Gross disease must be unifocal on Mammo/ MRI imaging
• COHORT II: Patients must have estrogen receptor (ER) and progesterone receptor (PR) analysis performed on core biopsy
• COHORT II: Patient must be able to tolerate lying in the prone position with arms extended forward
• COHORT II: Must be able to tolerate MRI scan with contrast
• COHORT II: At the time of enrollment, patients must have had bilateral mammograms within 6 months
• COHORT II: Patients must be willing to undergo breast cancer surgery minimally 4, maximally 6 weeks post APBI
• COHORT II: Patients with a history of non-breast malignancies are eligible if they have been disease free for 5 or more years prior to enrollment and are deemed by their physicians to be at low risk for recurrence; patients with the following cancers are eligible if diagnosed and treated within the past 5 years: carcinoma in situ of the cervix, carcinoma in situ of the colon, melanoma in situ, and basal cell and squamous cell carcinoma of the skin

Exclusion Criteria

• COHORT II:
• Age < 50 years
• Hormone unresponsive breast cancer
• T-2 (> 3.0 cm), T-3, stage III, or stage IV breast cancer
• N-1, N-2, or N-3 pathologic axillary nodes
• Mastectomy intended
• Unwilling to undergo anti-endocrine therapy
• Suspicious microcalcification, densities, or palpable abnormalities (in the ipsilateral or contralateral breast) unless biopsied and found to be benign
• Non-epithelial breast malignancies such as sarcoma or lymphoma
• Paget’s disease of the nipple
• Proven multicentric carcinoma (invasive or ductal carcinoma in situ [DCIS]) in more than one quadrant or separated by > 4 centimeters
• Any prior treatment with radiation therapy, chemotherapy, biotherapy, or hormone therapy for the currently diagnosed breast cancer prior to study enrollment
• Prior breast or thoracic radiation therapy (RT) for any condition
• Psychiatric of addictive disorders or other condition that in the opinion of the investigator would preclude the patient from meeting the study requirements