02 Dec MRI May Detect More Early Contralateral Breast Cancer But Not Prevent Advanced Disease
MedicalResearch.com Interview with:
Shiyi Wang, MD, PhD
Assistant Professor of Epidemiology (Chronic Diseases)
Yale School of Public Health
Medical Research: What is the background for this study?
Dr. Wang: As magnetic resonance imaging (MRI) of the breast has become part of medical care, there is increasing concern that this highly sensitive test might identify health problems that otherwise would not have had an impact on the patient – so called “overdiagnosis”. However, even if MRI use leads to overdiagnosis, the main “theoretical” benefit of early detection by MRI is to prevent future advanced diseases, the prognosis of which is deleterious. A systematic literature review found that, compared to mammography and/or ultrasound, MRI had a 4.1% incremental contralateral breast cancer (breast cancer in the opposite breast) detection rate. At this point, the impact of MRI on long-term contralateral breast cancer outcomes remains unclear.
Medical Research: What are the main findings?
Dr. Wang: Analyzing the Surveillance, Epidemiology, and End Results-Medicare dataset, we compared two groups of women who had breast cancer (one group receiving an MRI, and the other not) in terms of stage-specific contralateral breast cancer occurrences. We found that after five years, the MRI group had a higher detection rate of cancer in the opposite breast than the non-MRI group (7.2 % vs. 4.0%). Specifically, MRI use approximately doubles the detection rate of early stage contralateral breast cancer, but does not decrease the incidence of advanced stage contralateral breast cancer occurrences after a 5-year follow-up. Our results indicate that nearly half of additional breast cancers detected by the preoperative MRI were overdiagnosed, which means that many of these occult cancers not detected by MRI would not have become clinically evident over the subsequent 5 years. There was no evidence that MRI use was benefiting women because the rate of advanced cancer was similar in the MRI and the non-MRI groups.
Medical Research: What should clinicians and patients take away from your report?
Dr. Wang: Clinicians and patients need to carefully balance the risks and benefits of preoperative MRI. Preoperative MRI is associated with a large increase in the detection rate of early stage contralateral breast cancers, which leads to additional treatments of the opposite breast. This early detection by MRI use, and the associated treatments would increase women’s suffering and stress, but does not prevent advance diseases or improve health outcomes.
Medical Research: What recommendations do you have for future research as a result of this study?
Dr. Wang: Our analyses were restricted to older patients with median follow-up of 45 months. Future research focusing on the younger population with longer follow-up is necessary.
Shiyi Wang, MD, PhD (2015). MRI May Detect More Early Contralateral Breast Cancer But Not Prevent Advanced Disease