Intraoperative Radiotherapy for Korean Patients With Breast Cancer

Inclusion Criteria: * Histologically confirmed and newly diagnosed non-metastatic operable primary breast cancer * Primary tumor \<5cm, measured by ultrasonography - N0-3 (any N if resectable) and no evidence of distant metastasis (M) (isolated supraclavicular node involvement allowed) * Age ≥18-years women with good performance status (ECOG 0-1) * No breast operation is allowed except diagnostic biopsy * Women with ductal carcinoma in situ diagnosed by preoperative biopsy are allowed Exclusion Criteria: * Pregnancy or unwillingness to use a reliable contraceptive method in women of child-bearing potential. * Patients who received prior chemotherapy or radiotherapy for breast cancer * Patients who have history of cancer other than in situ uterine cervix cancer or non-melanoma skin cancer * The depth of tumor from skin measured by ultrasonography is less than 1cm. * Contraindications to breast conservative surgery * Multicentric breast cancer (tumors in more than one quadrant) * Diffuse malignant appearing microcalcification * Prior therapeutic radiation to the breast region * Small breast, which is not possible to achieve clear margins in relation to a cosmetically acceptable result * History of collagen vascular disease, such as active scleroderma and active lupus * Postoperative exclusion * Patients who require re-excision due to positive resection margin * The depth of cavity from skin after lumpectomy is less than 0.5cm