Breast cancer is the most common cancer in American women, accounting for over a quarter-million diagnoses a year.1 Studies indicate that early detection paired with appropriate treatment can have a large impact on long-term death rates.2 More accurate screening can also be helpful in detecting residual cancers after treatment.3
A wide range of techniques are currently used in this kind of diagnosis. Biopsies and biomarker-based diagnosis are used to distinguish benign and cancerous tissues. They're known for being usefully sensitive and selective but also for being expensive and time-consuming, labeling-dependent and for requiring highly-trained staff for proper implementation.4,5
The most common screening technology is mammography, which has limited effectiveness for dense breasts or for women under 40 and can miss small tumors.6, 7 Contrast-enhanced mammography is more accurate, but it involves high expense and radiation levels and isn't widely available.8
Other screening technologies include ultrasound — mostly in use as an ancillary technique — and positron emission tomography (PET), which provides accuracy for measuring the spread of tumors and the effectiveness of treatment. Microwave imaging has shown early promise as a low-cost alternative, but it is still experimental.9
There isn't yet a perfect solution either for early detection or for the tracking of cancers' progression and recurrence. One key screening tool that can increase accuracy in both these tasks is magnetic resonance imaging, or MRI.
Breast MRI assessment and detection of cancer
MRI has been tested as an adjunct to mammography and showed through the MRI assessments, an increase in detection rates over mammography alone, especially in finding lesions that required a high degree of sensitivity to locate. It showed particular usefulness in detecting tumors without being affected by the higher breast density common in younger patients.10
The sensitivity of MRI makes it a powerful tool when used in concert with other screening technologies like mammography and sonograms. MRI has demonstrated particular usefulness in catching residual cancers in those who have undergone breast conservation surgery. Its predictive value in confirming the absence of tumors is better than 98 percent.3
It sees employment in other kinds of treatment regimens as well. MRI is commonly used to monitor the response of cancers to radiation and chemotherapy. In fact, it's widely agreed that MRI is more accurate in assessing the effectiveness of chemotherapy than mammography.3
MRI's role in the field continues to advance. A new specialized variant of MRI has shown its own promise in reducing the time it takes to perform tests and process and interpret results. Called the First post-contrast Acquisition SubTracted (FAST) protocol, it mitigates the time and expense of the MRI process without sacrificing accuracy or leading to any statistically significant increase in the rate of false positives. Study on the FAST method is ongoing.11
All in all, while MRI cannot replace other screening technologies, it is clearly a crucial part of the suite of approaches to breast cancer detection — and its role will only continue to evolve in coming years. For those at high risk of breast cancer, it's worthwhile to look into the benefits of a breast MRI.
Breast MRI factors to consider
Breast MRI is not without potential flaws and drawbacks. It's still a relatively expensive and time-consuming procedure that might not be equally available to all patients, and alone, MRI doesn't necessarily provide a specific diagnosis. Its interpretation criteria are still evolving and can vary widely from one practitioner to the next.12
MRI's sensitivity and ability to detect smaller lesions that other processes might miss makes it useful in early detection and tracking. On the other hand, it has also been known to lead to false positive diagnoses or to diagnoses of risk that can lead to needlessly aggressive treatment.12
Finally, there is risk of adverse reaction in some patients to the contrast dye that's used in MRI. The potential risks that gadolinium can pose to some patients have been a hot topic of medical debate in recent years.13
All of this means that a breast MRI is a technique best approached with care, and that MRI is at its most effective when used alongside complementary imaging techniques and biopsies. It's crucially important that those seeking a breast MRI consult closely with their physician to make sure that its use is warranted and that risks can be minimized.
Be sure to seek out further guidance about breast cancer and ways to detect and treat it through organizations like the National Breast Cancer Foundation and other sponsors and promoters of Breast Cancer Awareness Month.
1. "U.S. Breast Cancer Statistics 2017." Web. 13 October 2018. <http://www.breastcancer.org/symptoms/understand_bc/statistics>.
2. A. Migowski. "Early detection of breast cancer and the interpretation of results of survival studies." Cienc. Saude Coletiva. 2015;20:1309.
3. Steven Halls. "Typical uses of MRI for breast cancer screening and diagnosis." Web. 13 October 2018. <https://breast-cancer.ca/mri-how-when/>.
4. T.W.F. Yen, et al. "The interplay between hospital and surgeon factors and the use of sentinel lymph node biopsy for breast cancer." Medicine. 2016;95:e4392.
5. E.J. Abel, et al. "Limitations of preoperative biopsy in patients with metastatic renal cell carcinoma: Comparison to surgical pathology in 405 cases." BJU Int. 2013;189:1692.
6. B.N. Hellquist, et al. "Effectiveness of population-based service screening with mammography for women ages 40 to 49 years with a high or low risk of breast cancer: Socioeconomic status, parity, and age at birth of first child." Cancer. 2012;118:1170–1171.
7. T. Onega, et al. "Facility mammography volume in relation to breast cancer screening outcomes." J. Med. Screen. 2016;23:31
8. T.C. Lewis, et al. "Contrast-enhanced digital mammography: A single-institution experience of the first 208 cases." Breast J. 2017;23:67.
9. T. Chen, et al. "Microwave biosensor dedicated to the dielectric spectroscopy of a single alive biological cell in its culture medium; Proceedings of the 2013 IEEE MTT-S International Microwave Symposium Digest (IMS); Seattle, WA, USA." 2–7 June 2013.
10. A. Rahlkhin, et al. "Breast MRI as an Adjunct to Mammography for Breast Cancer Screening in High-Risk Patients: Retrospective Review." Web. 13 October 2018. <https://www.ajronline.org/doi/10.2214/AJR.13.12264>.
11. M. Jain, A. Jain, M.D. Hyzy, et al. "FAST MRI breast screening revisited." J Med Imaging Radiat Oncol. Published online July 27, 2016.
12. Steven Halls. "More factors to consider about the uses of MRI in breast cancer screening and treatment." Web. 14 October 2018. <https://breast-cancer.ca/mrifacts/>.
13. Dave Fornell. "The Debate Over Gadolinium MRI Contrast Toxicity: A discussion on the safety of gadolinium-based contrast agents." Web. 12 October 2018. <https://www.itnonline.com/article/debate-over-gadolinium-mri-contrast-toxicity>.