Limitations of breast MRI
Overall, MRI is a diagnostic and monitoring test. It is costlier than mammography, and because it is not recommended in guidelines as a screening modality for most women, it is not typically covered by insurance. Abbreviated (rapid) MRI is a non-standardized imaging strategy being used at a few health centers. It has a shorter protocol overall than MRI, so it takes less time than current MRI and is less expensive, but there are few data on sensitivity and specificity. It is yet to be determined which populations could benefit from this newer technology.
As mentioned, 41% of women in the Bakker et al trial who were randomly assigned to breast MRI chose not to proceed with that exam even though it would have been at no cost to them.6 Anecdotally, some patients who have undergone MRI say they would forgo it a second time as a screening modality because it was a very unpleasant, stressful experience. It’s not a perfect test, although it is more sensitive than mammography.
Other options for following up dense-breast screening. Besides MRI and abbreviated MRI, the following modalities can be used to evaluate women found to have dense breasts with screening mammograms: CT mammography with contrast, molecular breast imaging, and ultrasonography.
Screening and treatment advances
3D mammography. In the US, the great majority of screening mammography now is performed with tomosynthesis, or what our patients sometimes call 3D mammography. In fact, it is approaching standard of care. Women whose screening mammography includes tomosynthesis are less likely to experience a so-called callback for additional imaging with diagnostic mammography or breast ultrasonography.14
Liquid biopsy. A potential major advancement for making decisions about when to treat cancers in general involves determining the biological behavior of a tumor, based on analysis of either circulating tumor DNA or proteins in the blood. As more experience with this new technology accumulates, the role of liquid biopsies for breast cancer will expand.15 Liquid biopsies for screening remain investigational for now, but they hold tremendous potential.
Noninvasive proteomics. With the development of noninvasive proteomic biomarkers obtained from blood, saliva, or nipple aspiration fluid, there exists the possibility of not just evaluating an image of a tumor seen on a mammogram, but actually studying the biological characteristics of that lesion.16 The cost of this technology is far less in terms of resources than MRI or molecular-based imaging, and actually reveals the flaws with using image-based screening. With proteomics, we can tell whether or not a lump is generating proteins that are going to make that disease biologically meaningful, and treatment decisions can be based on that information. This idea has the potential to disrupt our current breast cancer screening paradigm.
Advocacy’s role in mandating legislation
Many advocacy groups lobby on Capitol Hill for legislation related to health care, but we don’t feel that is the best way to make scientific decisions, and it’s not the way to do medicine. Passionate people, who truly believe that their outcome would have been different had something else been done, have every right to advocate, and should. However, without longer-term data focusing on breast cancer and overall mortality, rather than surrogate outcomes like interval cancers, it is not clear that routinely recommending supplemental MRI will improve survival for women with extremely dense breasts. Unfortunately, overall, earlier diagnosis of highly aggressive breast cancer tumors does not result in better outcomes for patients. ●