Statement: patients with Multi-focal breast cancer cannot be accepted for the primary trial.
Primary_evidence: Inclusion Criteria:   Patients' recurrences must have histologically confirmed ductal carcinoma in-situ, invasive ductal, medullary, papillary, colloid (mucinous), or tubular histologies.   Lesion size  3 cm treated with a tylectomy and whole breast irradiation (with or without tumor bed boost)   Unifocal breast cancer recurrence   Negative resection margins with at least a 2 mm margin from invasive and in situ cancer or a negative re-excision   Hormonal therapy is allowed. If chemotherapy is planned, the radiation is delivered first and chemotherapy must begin no earlier than two weeks following completion of radiation.   Signed study-specific informed consent prior to study entry. Exclusion Criteria:   Patients with distant metastatic disease   Patients with invasive lobular carcinoma, extensive lobular carcinoma in-situ, extensive ductal carcinoma in-situ (spanning more than 3 cm), or nonepithelial breast malignancies such as lymphoma or sarcoma.   Patients with multicentric carcinoma (tumors in different quadrants of the breast or tumors separated by at least 4 cm). Palpable or radiographically suspicious contralateral axillary, ipsilateral or contralateral supraclavicular, infraclavicular, or internal mammary lymph nodes unless these are histologically or cytologically confirmed negative.   Extensive intraductal component (EIC) by the Harvard definition, i.e. 1) more than 25% of the invasive tumor is Ductal carcinoma in situ (DCIS) and DCIS present in adjacent breast tissue. Presence of an EIC increases the chance of local recurrence, and as such, one might not be a candidate for repeat breast conservation.   Patients with Paget's disease of the nipple.   Patients with skin involvement.   Patients with collagen vascular disorders, specifically systemic lupus erythematosis, scleroderma, or dermatomyositis.   Patients with psychiatric, neurologic, or addictive disorders that would preclude obtaining informed consent.   Other malignancy, except non-melanomatous skin cancer, < 5 years prior to participation in this study.   Patients who are pregnant or lactating due to potential fetal exposure to radiation and unknown effects of radiation on lactating females.   Patients with known BReast CAncer gene (BRCA)1/BRCA 2 mutations.