Inclusion Criteria:

- Patients must have histologically confirmed in-situ or invasive breast carcinoma.

- Tis, T1, T2 invasive or non-invasive carcinoma of the breast; lesion less than 4 cm.

- Unifocal, multifocal or multicentric breast cancers that can be removed by nipple
sparing mastectomy with negative margins.

- Negative surgical margins.

- No extensive intraductal component or patient with distant metastases.

- Patients must be > 18 years of age.

- No concomitant or history of nipple discharge or skin involvement.

- No prior history of malignancy (less than 5 years prior to study entry), except
non-melanomatous skin cancer.

- No prior history of radiation to the chest.

- No collagenous disease (systemic lupus erythematosis, scleroderma, dermatomyositis)No
previous non-hormonal therapy including radiation or chemotherapy for current breast
cancer.

- No patients with Paget's disease of the nipple.

- No patients with co-existing medical conditions with life expectancy < 2 years.

- No pregnant or lactating women.

- ECOG 0 - 2.

- Signed study-specific informed consent form prior to the study entry.

Exclusion Criteria:

- Retroareolar breast cancer lesions.

- Concomitant or history of nipple discharge or skin involvement.

- Patient with distant metastases.

- Patient with extensive intraductal carcinoma.

- Any previously irradiated ipsilateral breast cancer.

- Patients with Paget's disease of the nipple.

- Patients with collagenous diseases, as systemic lupus erythematosis, scleroderma or
dermatomyosis.

- Other malignancy, except non-melanomatous skin cancer, less than 5 years prior to
participation in this study.

- Patients who are pregnant or lactating due to potential exposure of the fetus to RT
and unknown effects of RT to lactating females.

- Patients with BRCA 1-2 mutations.