Mammosite Breast Brachytherapy Optimization in the Treatment of Breast Carcinoma

Inclusion Criteria:

• Life expectancy of at least two years.
• Stage 0, I, or II breast cancer. If stage II, the tumor size must be 3 cm or less.
• On histological examination, the tumor must be DCIS or invasive adenocarcinoma of the breast.
• Surgical treatment of the breast must have been lumpectomy. The margins of the resected specimen must be histologically free of tumor (>2mm, DCIS and invasive). Re-excision of surgical margins is permitted.
• Gross disease must be unifocal with pathologic (invasive and/or DCIS) tumor size 3 cm or less. (Patients with microscopic multifocality are eligible as long as total pathologic tumor size is 3 cm or less.)
• Patients with invasive breast cancer are required to have axillary staging which can include sentinel node biopsy alone (if negative), sentinel node biopsy followed by axillary dissection or sampling with a minimum total of 6 axillary nodes (if sentinel node is positive), or axillary dissection alone (with a minimum of 6 axillary nodes). (Axillary staging is NOT required for patients with DCIS.)
• The patient must have the MammoSite catheter placed within 4 weeks or 28 days of the final surgery for their breast cancer (lumpectomy, re-excision of margins, or axillary staging procedure). Placement of a spacer for the MammoSite catheter is permitted at their final surgery.
• Patients with a history of non-ipsilateral breast malignancies are eligible if they have been disease-free for 2 or more years prior to randomization. Patients with the following cancers are eligible even if diagnosed and treated within the past 2 years: carcinoma in situ of the cervix, colon, melanoma in situ, and basal cell and squamous cell carcinoma of the skin. Patients with a prior diagnosis of ipsilateral breast cancer are ineligible.
• Must have 3 or fewer histologically positive axillary nodes with no extracapsular extension.
• Chemotherapy is permitted if planned for ≥2 weeks after removal of Mammosite catheter.
• Patient must be ineligible or have refused enrollment on the randomized trial RTOG 0413.

Exclusion Criteria:

• T2 (>3.0 cm), T3, stage III or IV breast cancer.
• More then 3 histologically positive axillary nodes.
• Axillary nodes with evidence of extracapsular extension.
• Palpable or radiographically suspicious ipsilateral or contralateral axillary, supraclavicular, infraclavicular or internal mammary nodes, unless biopsy proven to be negative for tumor.
• Suspicious microcalcifications, densities or palpable abnormalities in either breast unless biopsy proven to be benign.
• Non-epithelial breast malignancies such as sarcoma or lymphoma.
• Proven multicentric carcinoma in more than one quadrant or separated by more than 3 centimeters.
• Paget's disease of the nipple.
• History of invasive breast cancer or DCIS in the same breast.
• Surgical margins that cannot be microscopically assessed or are less then 2 mm.
• Collagen vascular disease, specifically dermatomyositis with a CPK level above normal or with an active skin rash, systemic lupus erythematosis or scleroderma.
• Pregnancy or lactation at the time of proposed radiation. Women of reproductive potential must agree to use an effective non-hormonal method of contraception during therapy.
• Psychiatric or addictive disorders or other conditions that, in the opinion of the investigator, would preclude the patient from meeting the study requirements.
• Patients with coexisting medical conditions in whom life expectancy is < 2 years.
• Patients with skin involvement, regardless of tumor size.
• Patients for whom treatment with the MammoSite catheter is not feasible, such as those with too little breast tissue between the skin and the catheter (<5mm).