Indications for MRI in Breast Cancer
Breast MRI is not universally recommended for all breast cancer patients but has specific indications where it provides valuable clinical information that impacts management and outcomes. 1
Established Indications for Breast MRI
Definite Indications:
- Clinically positive axillary nodes with occult primary breast cancer - When mammography and ultrasound fail to identify a primary tumor in the breast 1
- Paget's disease of the nipple - When mammography, ultrasound, and physical examination fail to identify a primary breast tumor 1
- Evaluation of response to neoadjuvant therapy - To define extent of disease, response to treatment, and potential for breast-conserving therapy 1, 2
Optional Indications (to be considered on a case-by-case basis):
- Dense breast tissue - Particularly in invasive cancer where mammographically occult disease is more likely 1, 2
- Preoperative staging - To evaluate extent of disease, especially for:
- Evaluation of multifocal or multicentric disease in the ipsilateral breast 1
- Screening of the contralateral breast - Particularly for women at increased risk 4
- Inconclusive mammographic findings - Such as asymmetry or architectural distortion that cannot be resolved with additional mammographic views or ultrasound 5, 6
Limitations and Considerations
False Positives and Overtreatment Concerns:
- MRI has a high percentage of false-positive findings (lower specificity than mammography) 1
- May lead to additional diagnostic workup including MRI-guided biopsies 1
- May increase mastectomy rates by identifying mammographically occult disease satellites that would have been adequately treated with lumpectomy and radiation 1
Evidence on Clinical Outcomes:
- Two prospective randomized studies showed no improvement in post-lumpectomy re-excision rates 1
- Retrospective studies show conflicting results regarding outcome benefits 1
- MRI staging alters surgical treatment in 7.8% to 33.3% of women, but no differences in local recurrence or survival have been demonstrated 1
Technical Requirements for Breast MRI
When performing breast MRI, the following are essential:
- Dedicated breast coil 1
- Imaging team experienced with MRI-guided breast biopsy 1
- Multidisciplinary treatment team involvement 1
Important Cautions
- Patients should not be denied breast conservation therapy based on MRI findings alone without additional tissue sampling to verify true malignant disease 1
- MRI findings tend to overestimate extent of disease 1
- No evidence shows that use of breast MRI increases rates of margin-negative resection 1
- The quality of breast MRI may vary significantly across practice sites 4