Outcomes following pre-operative MRI-guided bracketing in breast cancer patients

This study aimed to evaluate the surgical outcomes of patients undergoing magnetic resonance imaging-guided bracketing (MRI-B) prior to breast-conserving therapy (BCT).

This retrospective study included consecutive patients treated with BCT at our institution for invasive or in situ breast cancer between January 2016 and December 2022 and requiring MRI-B before surgery. Bracketing was performed by either inserting MRI-compatible wires or deploying clips under MRI guidance, with subsequent localization using mammography. Clinical, radiological, and pathological data were collected and correlated with positive surgical margins and imaging overestimation.

Among the 57 patients included, 10 (18 %) had positive surgical margins. Younger age (Mean: 56 vs 49 years) and the presence of ductal carcinoma in-situ (DCIS) or infiltrative lobular carcinoma (ILC) component (100 % vs 82 %) were most strongly associated with positive margins, although statistical significance was not reached (P = 0.11 and P = 0.149, respectively). MRI overestimated disease extent in 13 of 49 eligible patients (27 %). Overestimation was most strongly linked to isolated infiltrating ductal carcinoma (IDC; 38 % vs. 3 %, P = 0.008) and bracketed enhancing foci (54 % vs. 22 %, P = 0.084). During long-term follow-up, 2 patients (4 %) had local recurrence, and 3 patients (5 %) experienced distant recurrence.

MRI-B before BCT is associated with a clinically manageable rate of positive margins and local recurrence. However, optimizing patient selection is essential to minimize unnecessary bracketing and improve surgical outcomes.