Addressing Discrepant Clinical Practice Patterns in Preoperative Breast MRI Use

See also the article by Simmons et al in this issue.

Nhat-Tuan Tran, MD, serves as the quality and safety lead in the breast imaging department and as associate breast imaging fellowship director. He is an assistant professor in the department of radiology at Denver Health. His research interests include evaluating emerging techniques to reduce barriers to care in cancer treatment.

Randy C. Miles, MD, MPH, serves as the chief of breast imaging at Denver Health with oversight over the breast division’s clinical, research, and educational programs. He also serves as the Associate Director for Research in the radiology department. Dr Miles’ clinical, research, and public health efforts center around using innovative techniques to identify barriers to breast cancer screening, create patient-centered initiatives to improve access to breast imaging services, and examine how to improve delivery of high-quality, guideline-concordant breast care for all patients.

Achieving adequate surgical margins for breast cancer is a primary goal of breast conservation surgery. Breast MRI is often used preoperatively in patients with recently diagnosed breast cancer to assess extent of disease and to guide appropriate surgical management. Breast MRI demonstrates high sensitivity (95%–100%) in cancer detection and provides benefit in the evaluation of mammographically occult disease in the ipsilateral and contralateral breasts. While consensus guidelines have not been established, relative indications for breast MRI in patients with breast cancer include young age, lobular histology, and mammographically dense breast tissue. Clinical practice patterns remain highly variable across institutions, however, largely based on surgeon preference (1).

In this issue of Radiology: Imaging Cancer, Simmons and colleagues (2) retrospectively evaluated racial disparities in preoperative breast MRI use and surgical margin outcomes among patients with newly diagnosed breast cancer. Patient data were obtained from self-identified White and Black patients with breast cancer who underwent breast surgery between 2008 and 2020 at a single institution. Preoperative breast MRI use and positive margin rates were determined from the electronic medical record. Differences in preoperative breast MRI use across racial subgroups and positive margin rates across racial cohorts were compared and tested for significance using the χ² test.

Of 28 384 women included in the final patient cohort, 9305 (32.78%) underwent preoperative breast MRI. Black patients had a significantly lower MRI use rate compared with White patients (29.85% vs 33.10%, P < .001). The overall positive margin rate was 4.24% (672 of 15 863). Patients who underwent preoperative MRI had a significantly lower positive surgical margin rate compared with those who did not (2.90% vs 4.78%, P = .03). Black patients had a significantly higher positive surgical margin rate within the no-MRI cohort compared with White patients (6.17% vs 4.63%, P = .03), while there was no difference observed in positive surgical margin rates between Black and White patients (3.17% vs 2.87%, P = .90) within the MRI cohort.

While increased utilization of mammography screening and advances in breast cancer therapies have contributed to a substantial decline in breast cancer mortality over the past 50 years, not all women have benefitted equally. Black women have the lowest 5-year breast cancer survival rate compared with all other racial and ethnic groups for each stage of disease and every breast cancer subtype. Cumulative evidence supports that racial disparities in breast cancer survival are influenced by multiple factors including biologic factors, socioeconomic status, and system-level barriers (3). This study provides evidence that discrepant preoperative breast MRI use among racial groups may represent a contributing factor. Black patients with recently diagnosed breast cancer were less likely to undergo preoperative breast MRI and more likely to have positive surgical margins when preoperative MRI was not performed, in comparison to White patients.

Given the importance of identifying gaps in care experienced by historically vulnerable groups, studies such as the one performed by Simmons et al help to highlight the importance of addressing health care inequities in imaging utilization. However, it is also important to note some limitations. Racial subgroups were not matched for relative indications associated with breast MRI use such as young age at diagnosis, dense breast tissue, and lobular histology. These are factors shown to influence both radiology recommendations for breast MRI and surgeon decision-making. In addition, confounding factors including socioeconomic status, which has been shown to largely influence breast imaging utilization among Black women, were not included. Last, limited racial diversity in the preoperative breast MRI and positive surgical margin cohorts may limit generalizability. Further studies, including increasing numbers of Black women and those from other racial and ethnic groups, are necessary to fully evaluate the impact of race and ethnicity on preoperative MRI use and the benefit of MRI assessment of extent of disease following a breast cancer diagnosis.

It is also important to highlight that evidence supporting preoperative breast MRI use in the setting of newly diagnosed breast cancer is mixed (1,4). While pooled analysis has demonstrated benefit, including lower rates of positive margins and reduced reoperation rates in patients undergoing preoperative MRI compared with those not undergoing MRI for recently diagnosed breast cancer, multiple randomized controlled trials have demonstrated no difference in local recurrence or overall survival between the two groups. In addition, multiple studies demonstrate that breast MRI may contribute to false-positive examinations, leading to unnecessary procedures and increased costs, delays in surgery, and increased mastectomy rates despite questionable significance of additional disease detected with MRI.

Despite the lack of consensus opinion on preoperative breast MRI use in patients with newly diagnosed breast cancer, the impact and clinical applicability of this study has wide-ranging implications. Black women are both more likely to be diagnosed at a younger age and to develop more aggressive disease, factors typically associated with increased preoperative breast MRI utilization. The authors highlight implicit bias as a potential reason for this paradox, which can represent a major contributor to patient exclusion from the decision-making process. Shared decision-making (SDM), which involves patient-provider collaboration in medical decision-making by incorporating patient preferences and values into the clinical context, is a critical process when addressing recommendations, particularly those without consensus guidelines (5). Barriers to effective SDM in vulnerable groups are well-documented, including medical distrust, power imbalances, and cultural competency. Addressing such factors and how they interact with other social determinants of health, including but not limited to health literacy, socioeconomic status, and geographic access to services, are key in establishing health equity in imaging utilization.

Efforts to improve SDM utilizing a patient-centered approach among Black patients may help address discrepant practice patterns demonstrated in this study. This is particularly important as inconsistencies in preoperative MRI utilization across racial subgroups may be associated with downstream clinical consequences that contribute to disparities in breast cancer mortality (3). Providers, including radiologists, should be educated about the importance of SDM, particularly among vulnerable groups, and should be provided training in how to use SDM effectively in their practice (5). While time constraints are often cited as a barrier, evidence supports that the average time required for SDM conversations is less than 5 minutes. For more effective interactions, supplementing conversations with educational materials, decision tools, and resources that include pictorial representations and written in plain language may help fill knowledge gaps about the advantages and disadvantages of preoperative breast MRI use.

The use of breast MRI in newly diagnosed patients remains controversial. Advances in artificial intelligence and radiomics may eventually provide objective measures to support clinical decision-making, including supporting appropriate patient selection and improving identification of clinically significant disease. Until this point, establishing standard recommendations for preoperative breast MRI use among all patients with newly diagnosed breast cancer and ensuring all patients are knowledgeable of the advantages and disadvantages of this practice through effective SDM may help to reduce implicit bias. Lack of clinical consensus guidelines on preoperative breast MRI in patients with newly diagnosed breast cancer requires increased patient engagement and objective measures for patient selection to reduce discrepant clinical practice patterns.