5 Fraction Stereotactic Partial Breast Irradiation Using the GammaPod System in Treating Patients with Stage 0-IIa Breast Cancer

Inclusion Criteria

• Ductal carcinoma in situ (DCIS) or invasive ductal, medullary, papillary, mucinous (colloid), lobular, or tubular histologies.
• Eastern Cooperative Oncology Group (ECOG) performance status 0-2.
• Women of child-bearing potential must agree to use adequate contraception (barrier method of birth control- condom or diaphragm and spermicidal foam; intrauterine device, prescription birth control pills, or abstinence) prior to study entry, for the duration of study participation, and for 90 days following completion of therapy. Should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately. * A female of child-bearing potential is any woman (regardless of sexual orientation, having undergone a tubal ligation, or remaining celibate by choice) who meets the following criteria: ** Has not undergone a hysterectomy or bilateral oophorectomy; or ** Has not been naturally postmenopausal for at least 12 consecutive months (i.e., has had menses at any time in the preceding 12 consecutive months).
• Appropriate staging studies identifying as American Joint Committee on Cancer (AJCC) clinical stage 0, I, IIA (Tis, or T1-T2, N0 [N0i+]). The tumor size must be 3 cm or less.
• Surgical treatment of the breast with lumpectomy with histologically confirmed margins free of tumor (no ink on margin) for invasive disease, and at least 2mm for ductal carcinoma in situ. (Re-excision of margins is permitted).
• Gross disease within the breast must be unifocal. (Patients with microscopic multifocality are eligible as long as the total extent of tumor, gross and microscopic, occupies a volume with greatest dimension extent of 3 cm or less (regarding the largest diameter of volume occupying space).
• Patients with invasive disease are required to have axillary staging including: sentinel node biopsy or axillary dissection. If patients are over age 65, axillary staging is at the discretion of the physician. Patients with DCIS are not required to have axillary staging.
• Ability to understand and the willingness to sign a written informed consent.

Exclusion Criteria

• Clinical T2 (> 3.0 cm), T3, N1, stage III, or stage IV breast cancer.
• Evidence by physical examination or mammography of other suspicious masses, densities, or microcalcifications in either breast, unless biopsied and found to be benign.
• Patients with non-epithelial breast malignancies such as sarcoma or lymphoma are excluded.
• Paget’s disease of the nipple.
• Previous thoracic or breast radiation on ipsilateral side. Contralateral breast radiation is not excluded.
• Treatment plan that includes ipsilateral whole breast or ipsilateral regional nodal irradiation.
• Any prior treatment with radiation, endocrine therapy, or chemotherapy (in the neoadjuvant setting) for currently diagnosed breast cancer prior to GammaPod treatment- adjuvant chemotherapy is acceptable.
• Patients with active collagen vascular disease, specifically dermatomyositis with a creatine phosphokinase (CPK) level above normal or active skin rash, systemic lupus erythematosus, or scleroderma, no other exclusions.
• Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, immunosuppressed patients or psychiatric illness/social situations that would limit compliance with study requirements.
• Subjects must not be pregnant or nursing due to the potential for congenital abnormalities and the potential of this regimen to harm nursing infants.
• If the lumpectomy cavity is completely outside of the vacuum assisted breast cup, then patient should not be treated on the GammaPod secondary to concerns of reproducibility.
• Transplant patients or any patients on immunosuppressive therapy.
• Breast size that is too large for the breast cup immobilization device.