Single Fraction High-Gradient Partial Breast Irradiation in Treating Patients With Low-Risk Stage 0-I Breast Cancer

This is a phase I/II study which will evaluate the complication rates, local control,
cosmetic results, and quality of life of single fraction high gradient partial breast
irradiation (HG-PBI) when used as the sole method of radiation therapy for patients with
pathologic stage 0 (=< 2 cm) or I carcinoma of the breast treated with partial mastectomy
with histologically assessed negative surgical margins.

Inclusion Criteria:

- AJCC 7th Edition stage 0 or I (TisN0 ≤ 2 cm or T1N0) histologically confirmed
carcinoma of the breast, treated with partial mastectomy. Axillary sampling is
required only for cases of invasive cancers. Tumor size is determined by the
pathologist. Clinical size may be used if the pathologic size is indeterminate.
Patients with invasive cancer must have no positive axillary lymph nodes with at least
6 axillary lymph nodes sampled or a negative sentinel node.

- Negative histologic margins of partial mastectomy or re-excision specimen. Margins
generally are positive if there is invasive or noninvasive tumor at the inked
resection margin, close but negative if the tumor is within 2 mm of the inked margin
and negative if the tumor is at least 2 mm away from the inked edge.

- Invasive ductal, lobular, medullary, papillary, colloid (mucinous), tubular
histologies, or mixed histologies (lesions ≤ 2 cm) that are estrogen or progesterone
receptor positive and do not exhibit HER2/neu gene amplification OR ductal carcinoma
in situ (lesions ≤ 2 cm).

- Systemic therapy, if planned, must be adjuvant in nature and not be scheduled to begin
for at least 4 weeks after completion of HG-PBI.

- Good candidate for treatment per protocol in the judgment of the PI and/or treating
physician following simulation.

- Postmenopausal status.

- Age ≥ 50 years at diagnosis.

- Able to understand and willing to sign IRB-approved written informed consent document.

- English speaker.

Exclusion Criteria:

- Presence of distant metastases.

- In situ lobular carcinoma or nonepithelial breast malignancies such as sarcoma or
lymphoma.

- Proven multicentric carcinoma (tumors in different quadrants of the breast, or tumors
separated by at least 4 cm) with other clinically or radiographically suspicious areas
in the ipsilateral breast unless confirmed to be negative for malignancy by biopsy.

- Premenopausal status.

- Histologically confirmed positive axillary nodes in the ipsilateral axilla. Palpable
or radiographically suspicious contralateral axillary, supraclavicular,
infraclavicular, or internal mammary nodes, unless there is histologic confirmation
that these nodes are negative for tumor.

- Prior non-hormonal therapy for the present breast cancer, including radiation therapy
or chemotherapy.

- Diagnosis of systemic lupus erythematosis, scleroderma, or dermatomyositis.

- Diagnosis of a coexisting medical condition which limits life expectancy to < 2 years.

- Diagnosis of psychiatric or addictive disorders that would preclude obtaining informed
consent.

- History of other malignancy ≤ 5 years previous with the exception of basal cell or
squamous cell carcinoma of the skin which were treated with local resection only or
carcinoma in situ of the cervix.

- Paget's disease of the nipple.

- Skin involvement, regardless of tumor size.

- Unsatisfactory breast for HG-PBI as determined by the treating physician. For example,
if there is little breast tissue remaining between the skin and pectoralis muscle
after surgery, treatment with HG-PBI is technically problematic.

- Partial mastectomy so extensive that the cosmetic result is fair or poor prior to
HG-PBI as determined by the treating physician.

- Surgical margins which cannot be microscopically assessed or are positive at
pathological evaluation.

- Time between final definitive breast procedure to HG-PBI simulation is greater than 8
weeks.

Inclusion of Women and Minorities

-Women and members of all races and ethnic groups are eligible for this trial. Because
breast cancer occurs rarely in men, men will not be recruited for participation.