Characterizing Outcomes after Intra-Operative Radiation Therapy Using the IntraBeam System in Patients with Early Stage Breast Cancer

Inclusion Criteria

• Female gender
• Age >= 45
• cT1-2N0, < 3.5cm invasive breast cancer, estrogen-receptor positive or ductal carcinoma in situ (DCIS) of breast, grade 1-2, mammographically detected, < 2.5 cm, estrogen-receptor positive
• Suitable for breast conserving surgery
• No contraindication to radiation
• Mammogram within 6 months of planned procedure
• Fitness for lumpectomy under general anesthesia
• Planned to receive IORT
• Patients with a history of ipsilateral cancer and/or prior in-field radiation are eligible, as IORT would likely be less toxic than repeat whole or partial breast external beam radiation and can allow patients to avoid mastectomy who wish to do so

Exclusion Criteria

• Known axillary lymph node positive breast cancer (negative biopsy not required)
• Multicentric cancer in the same breast as diagnosed by clinical examination, mammography, ultrasound, magnetic resonance imaging (MRI) or pathologic assessment, not amenable to excision with negative margins with a single lumpectomy
• Patients known to have BRCA 1/2 gene
• Patients undergoing neoadjuvant chemotherapy