Role of Preoperative MRI in Breast-Conserving Surgery

By: Emily Rhode
Posted: Tuesday, May 30, 2023

A first-of-its-kind trial used randomized stratification based on mammographic density to evaluate the performance of preoperative MRI in different subgroups of patients with breast cancer. It has shown that the use of breast MRI may lead to higher mastectomy rates and does not appear to impact oncologic outcomes, according to an article published in Breast Cancer Research and Treatment.

“The core issue about the MRI exam to preoperatory staging is the unnecessary mastectomies, due to false-positive findings,” said Bruna Salani Mota, MD, of Universidade de São Paulo, Brazil, and colleagues. “Our results show that preoperative breast MRI did not change the local recurrence and overall survival rates in breast-conserving surgery candidates.”

The phase III, randomized, open-label, single-center BREAST-MRI Trial included female patients with stage 0 to III breast cancer who were eligible for breast-conserving surgery. Participants clinical breast examination, mammography, and ultrasound. Breast density was measured using mammography, and patients were then randomly assigned and stratified based on breast density to receive or not receive preoperative MRI evaluation. A total of 524 patients were included in the trial, with 257 in the MRI group and 267 in the control group.

The surgical approach for the intervention group was modified based on the MRI findings, with some patients transitioning from lumpectomy to mastectomy depending on two criteria: 50% threshold and/or multifocality and breast patient volume evaluation not supporting breast-conservating surgery.

Local relapse–free survival was the primary outcome of the trial, and secondary outcomes included overall survival, the proportion of patients requiring mastectomy, and the reoperation rate. The 5.9-year local relapse–free survival rates were 99.2% and 98.9% with MRI and without (hazard ratio [HR] = 1.37; 95% confidence interval [CI] = 0.59–3.19; P = .8). A total of 21 patients (8.3%) in the MRI group had a change in surgical management and underwent mastectomies versus 1 patient in the control group. The researchers found no significant difference in the rate of reoperation between the MRI and control groups.

Disclosure: The study authors reported no conflicts of interest.

Breast Cancer Research and Treatment

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