This clinical trial is being conducted to find out the effects (good and bad) of giving the full radiation treatment for breast cancer as a single dose of radiation during surgery for breast cancer. This single fraction intraoperative radiotherapy with electrons will study the toxicity, local control and cosmetic outcome.

For patients with certain types of breast cancer, one standard treatment is breast conserving surgery or lumpectomy (surgery to remove abnormal tissue or cancer from the breast and a small amount of normal tissue around it) followed by breast radiation. The radiation treatment in this situation usually lasts 3 to 5 1/2 weeks followed by 5-8 daily localized irradiation (or boost) treatments at the site where the lump was removed. During this study, the single dose of electron irradiation given at the surgical site during the operation will replace the radiation given after surgery.

Inclusion Criteria:

• Histological proven invasive breast carcinoma ductal, lobular and/or Ductal Carcinoma in situ
• Age > 40 years
• Karnofsky performance status > 70%
• Tumor. Single discrete tumor or focal microcalcifications that can be imaged on a specimen radiograph or multifocal disease within the same quadrant with a maximum dimension of equal to or less than 2.5 cm
• Nodal Status: preoperatively N0
• Clear surgical margins: R0
• All grades G1 - G3
• Any hormonal receptor and HER-2 status
• Informed consent

Exclusion Criteria:

• Gender: male
• Tumor size: more than 2.5 cm
• Nodal status greater than or equal to N1 pathologically
• Multicentricity
• Previous radiotherapy to the involved breast
• Karnofsky Index < 70%
• Mixed connective tissue diseases e.g. rheumatoid poly arthritis, thromboangitis obliterans, systemic lupus
• Distant metastases
• Pregnancy in woman of child bearing age
• Unable to provide written consent