Dr. Lia Bartella: Breast MRI- How to play the field
Magnetic Resonance imaging of the breast is rapidly becoming incorporated into clinical practice. Indications for breast MRI include:
- evaluation of silicone implants
- staging of known breast cancer
- monitoring response to chemotherapy
- assessing recurrence/ problem solving
- high risk screening
Several studies have demonstrated that breast MRI can detect multifocal, multicentric and contralateral cancer that other imaging modalities fail to detect. This may result in change of the surgical management of the patient. Staging of breast cancer with MRI is recommended for women with dense breasts on mammography, mammographically occult cancer, invasive lobular cancer, posterior tumors when chest wall invasion is suspected and in patients with positive surgical margins after a lumpectomy.
Breast MRI can be used to measure the degree and rate of response to guide individual treatment, allowing therapy to be modified. Mri has been shown to be superior to mammography and clinical exam in assessing response to chemotherapy, with close correlation with pathology. The ACRIN 6657 study will assess the accuracy of measuring response and extent of disease after chemotherapy, with MRI.
Breast MRI is used to differentiate recurrent tumor from scar as this can be difficult to do clinically and mammographically. Breast MRI is excellent when looking for a breast primary cancer in the presence of metastatic disease. It is used as a problem solving tool when conventional imaging methods fail to answer a specific question.
Although mammography has been shown to save lives it has limitations especially in screening the younger patients. Mammography is less sensitive for uncalcified DCIS, invasive lobular cancers and in patients with the BRCA 1/2 gene .Studies have shown that when used in conjunction with mammography, Breast MRI increases the sensitivity for breast cancer detection in the high risk population. No study has yet shown that cancers found by MRI decrease mortality from breast cancer.Annual screening with MRI has at last been recommended for high risk women both in the UK and the US. There is no data to support the use of MRI in screening women at normal risk. Screening MRI does NOT replace mammography. Patient counseling is critical when recommending breast MRI as many 6 month follow ups and biopsies are recommended for a small percentage of cancers detected.