Breast MRI is a fairly new technology, but it has been well studied. It is now used routinely in many patients with breast cancer. It has been shown to be useful in detecting areas of cancer that cannot be seen using other types of scans or tests.

The purpose of this study is to see how often MRI can find other areas of cancer in women with one area of breast cancer, and to determine how having the MRI test affects their treatment. The purpose is also to study any areas of abnormality seen on your MRI with special methods that allow the images of your breast tissue and the microscopic analysis of your breast tissue to be compared very carefully. The study also aims to follow women who enter the study over a 10-year period to determine how often the breast cancer comes back.

Inclusion Criteria:

• Age less than 60 at time of consent
• Clinical stage is consistent with Stage 0 or Stage I T1mic at presentation
• Core biopsy proven DCIS or DCIS with microinvasion (invasion ≤0.1 cm), prior to enrollment
• Breast surgery to be performed at MSKCC
• Informed consent obtained
• Female

Exclusion Criteria:

• Age 60 or over at time of consent
• Patients who are pregnant or nursing
• Patients with contraindications to breast conservation
• Excisional biopsy of DCIS or DCIS with microinvasion, prior to enrollment
• Patients with any contraindications to MRI including pacemaker, tissue expander, other metallic surgical implants, weight over 350 lb., previous gadolinium reaction, metal fragments in eye