1. In a retrospective review of over 6000 patients with breast cancer, pre-operative breast magnetic resonance imaging (MRI) does not significant improve the detection of clinically significant contralateral breast cancers (CBC).
Evidence Rating Level: 3 (Average)
Study Rundown: In breast cancer patients, pre-operative MRI are commonly used for screening of CBCs. However, given the increased financial costs as well as the psychological stress of false-positive findings, it is unclear whether routine MRI scans in this patient population offer significant benefit. The purpose of this retrospective cohort study was to evaluate the effect of pre-operative MRI use on CBC incidence.
The study reviewed the 5-year outcomes data of over 6000 breast cancer patients that underwent pre-operative breast MRI scans and over 32 000 propensity-matched breast cancer patients that did not undergo pre-operative breast MRI. At the conclusion of the study, patients in the breast MRI group demonstrated an increased frequency of synchronous (<6 months after diagnosis) CBC diagnosis compared to the non-MRI group. However, using statistical prediction models, the majority of these cases were likely in-situ CBCs and stage I disease at 5-year follow-up. There was no significant association between breast MRI use and detection of stage II to IV CBC. The results of this study support the hypothesis that pre-operative MRI may not significant detected clinically significant CBC, which may lead to over-diagnosis. The study was limited to patients greater than 67 years of age; thus, the results are not generalizable to younger patients, who may benefit more from early diagnosis of CBCs. Additionally, the study focused only on CBC recurrences. Additional prospective trials in younger patients as well as ipsilateral disease recurrence are needed to clarify the role of pre-operative MRI in breast cancer patients.
In-Depth [retrospective cohort]: This study was a retrospective review on the incidence of CBC in breast cancer patients with or without pre-operative breast MRI scans. The study reviewed all patients with stage I to II breast cancer pages aged 67 to 94 from the Surveillance, Epidemiology, and End Results (SEER)-Medicare database in the United States. Overall, the study reviewed 6737 breast cancer patients with pre-operative MRI and 32 234 propensity matched breast cancer patients that did not undergo MRI. At the conclusion of the study, the pre-operative MRI group demonstrated higher rate of synchronous in-situ CBC (47.9 vs 12.9 per 1000 person-years; p > 0.001) and invasive CBC (78.6 vs 30.0 per 1000 person-years; p > 0.001). In a Markov prediction model simulation, pre-operative breast MRI use was associated with increased detection of in-situ and early stage CBC occurrences without significant increase in detection of stage II to IV CBC cases.
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