Risk versus Benefit of Surveillance Breast MRI: A Sticky Wicket

Surveillance Strategies After Primary Treatment for Patients with Invasive Lobular Carcinoma of the Breast: Method of Local Recurrence Detection After Breast-Conserving Surgery

BACKGROUND

Invasive lobular carcinoma (ILC) is the second most common subtype of breast cancer. Although mammography is known to have low sensitivity for ILC, there are no data to guide the optimal surveillance after treatment. We explored surveillance strategies after breast-conserving surgery (BCS) for ILC and determined the proportion of imaging-detected recurrences versus interval cancers.

METHODS

From an institutional database of 813 women, we retrospectively identified patients who underwent BCS for stage I-III ILC and subsequently had a recurrence. We categorized patients by surveillance strategy and determined the modality of recurrence detection. Interval cancer rates for local recurrences were compared across surveillance strategies using the Chi-square test. We evaluated overall survival with the log-rank test and a Cox proportional hazards model.

RESULTS

We included 58 patients with ILC who had a recurrence after BCS. Of these, 22 (37.9%) had local recurrence, 27 (46.6%) had distant recurrence, and 9 (15.5%) had both local and distant recurrence. Most patients underwent routine mammographic surveillance (65.2%), with 19.6% having supplemental breast magnetic resonance imaging (MRI) and 15.2% having no surveillance. The interval cancer rate was significantly higher in the mammographic surveillance group compared with the MRI surveillance group (61.9% vs. 16.7%; p < 0.001).

CONCLUSION

In this study of patients with recurrence after BCS for primary treatment of stage I-III ILC, we found that most local recurrences were not detected by surveillance mammography. These data support further investigation of supplemental imaging beyond mammography specifically for patients with ILC who undergo BCS.

Abbreviated Protocol Breast MRI

OBJECTIVE. Patients with dense breast tissue are seeking supplemental screening because of the limited sensitivity of mammography. Abbreviated protocol (AP) breast MRI is attractive because it offers a higher cancer detection rate, shorter scan time, and lower cost than full MRI. This article explores the issues of balancing the benefits of AP MRI with safety concerns about gadolinium-based contrast agents, lack of standardization of protocols and field strengths, potential decrease in performance metrics, and potential for overdiagnosis. CONCLUSION. Important questions need to be addressed before AP MRI can be used routinely for breast cancer screening. Evidence is lacking from well-designed prospective trials that can confirm the accuracy and efficacy of AP MRI are comparable with those of other breast imaging modalities. Determining which patients benefit most from AP MRI will help shape future screening guidelines.