Early stage breast cancer: Should MRI factor into conservation surgery, mastectomy or bilateral mastectomy?
Lawrence Solin, MD
MRI shows no benefit but still useful
We do not know the answer at this time. There is very little published information on outcomes in patients screened with MRI vs. those screened only with mammography. That is where the real problem lies. The data do not support recommending MRI for all women in contemporary practice. It is clear that some selective groups of women should receive MRI, such as patients with a family history of the disease, patients with BRCA mutations or patients with implants. But that is far different from all women receiving an MRI.
In a recent study (J Clin Oncol. 2008;26:386-391), my colleagues and I found no difference in outcome at eight years between patients who did and patients who did not receive MRI prior to breast conservation. We had postulated that those who received MRI would have a better local control rate because of better imaging of the breast tissue, but that did not happen. Although MRI can detect additional disease, it is also clear that radiation therapy, sometimes along with systemic therapy, is sufficient to control the disease.
Many of us thought that MRI would be valuable, and our study was very sobering in that MRI did not show a benefit. We have to be careful here. This should not be interpreted to mean that nobody needs an MRI, because that is not true. We still need to learn who benefits most. MRI is a powerful tool that we have not yet learned to use in its most effective fashion.
The standard breast conservation treatment works very well, with a very low risk of local recurrence. The treatment is so effective that it would be hard to demonstrate the value of MRI in that setting. To demonstrate such a benefit, a trial would require thousands of patients and is not feasible at the present time.
Lawrence Solin, MD, is the Chairman of the Department of Radiation Oncology at Albert Einstein Medical Center in Philadelphia.
Huong Le-Petross, MD, FRCPC
MRI on a case-by-case basis
There is a general misperception that all radiologists want to perform MRI on all newly diagnosed breast cancer. That is not true. At our institution, all patients with newly diagnosed breast cancer receive ultrasound as part of the staging work-up. Ultrasound is cheaper and more comfortable for the patient and also allows for assessment of the infraclavicular and supraclavicular nodes, which are challenging regions to access on MRI. Breast MRI is used only for selective cases.
To date, we do not know the impact of breast MRI on morbidity and mortality. At the same time, we also do not know the impact of detecting microscopic disease on morbidity and mortality, regardless of the imaging modality used MRI, digital mammogram, positron emission tomography or others.
It is important to tailor the use of MRI on a case-by-case basis. In my opinion, breast MRI should be considered in the following situations: for patients with newly-diagnosed invasive lobular carcinoma who have heterogeneously dense or extremely dense breast parenchyma on mammogram; for patients who are high risk; and for patients with metastatic adenopathy of unknown primary origin. MRI would also be helpful in problem-solving unusual and challenging cases presenting on conventional imaging modalities.
In a previous study (J Clin Oncol. 2002;20:3413-3423), Solin and colleagues found that breast MRI results altered management of the disease. According to their subsequent study, the change of management did not affect outcome. The study period in the most recent study was 1992 to 2001. Breast MRI has changed dramatically between that time and now. We are now able to perform bilateral parallel imaging instead of requesting patients to return. The resolution has also improved. Breast MRI technology is constantly changing and evolving. It is possible that as this technology matures, the use of breast MRI may be associated with an improvement in outcome in a subtype of breast cancer, such as invasive lobular carcinoma.
Huong Le-Petross, MD, FRCPC, is an Assistant Professor of Radiology at The University of Texas M.D. Anderson Cancer Center.