MRI detection of multi focal breast carcinoma: Report from the International Breast MRI Consortium
Reviewer: Charles Wood, MD
Abramson Cancer Center of the University of Pennsylvania
Last Modified: June 5, 2004
Presenter: M. D. Schnall
Presenter's Affiliation: University of Pennsylvania
Type of Session: Scientific
- Single institution studies have suggested that MRI more accurately determines the extent of cancer within the breast compared to mammography, increasing the ability to detect multi-focal disease and potentially alter the treatment approach
- This study was undertaken to estimate the relative yield and positive predictive value of MRI and mammography with respect to addtional foci of cancer within the breast, and to compare the features of the cancer detected
Materials and Methods
- This is a prospective study of 1004 women with suspicious clinical or mammographic findings undergoing MRI prior to biopsy of the index lesion
- Patients were enrolled at 17 centers in the US, Canada, and Germany
- In addition to characterizing the index lesion, any incidental lesions discovered by MRI or mammogram were noted; incidental lesions were defined as being at least 2cm from the index lesion with the rationale that this would be outside any reasonable surgical margin
- All index lesions and any suspcious incidental lesions (BIRAD score 4 or 5) were biopsied
- 428 out of 1004 women had index lesions diagnosed with cancer
- At least one incidental lesion was detected by MRI in 103 women and by mammography in 36 women
- 78 out of 103 MRI-detected and 20 out of 36 mammography-detected incidental lesions were biopsied
- No signicant differences between the positive predictive value of each technique, as 56 out of 78 (72% PPV) MRI-detected incidental lesions and 17 out of 20 (85% PPV) mammography-detected lesions were malignant
- Estimated yield in detecting incidental malignant lesions (multi-focal disease) was significantly higher by MRI (17%) compared to mammography (7%)
- The characteristics of MRI-detected cancers were no different than mammography-detected cancers with respect to histology or grade
- The majority of incidental lesions detected only by MRI occured in women with increased breast densities
- MRI provides increased ability to detect multi-focal disease in women with breast cancer as compared to mammography
- The positive predictive value of each technique was similar
- the IBMC is considering the recommendation of including MRI evaluation of the breast as part of the standard work-up prior to biopsy
MRI is a superior tool for detecting multi-focal lesions in women diagnosed with breast cancer. This finding can significantly impact on the recommended surgical proceedure. A simple lumpectomy may not be the appropriate surgery in these patients and more extensive resection or mastectomy may be the optimal approach. There was no follow-up reported to show a clinical effect from MRI evaluation, as this was not part of the study design. However, the relatively high yield of second cancer foci leads one to believe that the study might well imply clinical significance. Including MRI in the standard evaluation of the patient prior to biopsy would have significant financial implications and an ACR cost-benefit study is currently ongoing to address this issue.
Oncolink's ASCO Coverage made possible by an unrestricted Educational Grant from Bristol-Myers Squibb Oncology.
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