Standardized Preoperative MRI Pathway Aimed to Improve Surgical Planning in Breast Malignancy

Purpose: At our comprehensive breast center, bilateral breast magnetic resonance imaging (MRI) with and without intravenous contrast is routinely ordered as part of preoperative evaluation for localized invasive breast cancer and ductal carcinoma in situ (DCIS), despite evidence suggesting it may not always be necessary. This study assessed how MRI contributes to preoperative staging accuracy by comparing tumor dimensions on MRI, mammography, and ultrasound with final pathology. Secondary outcomes included re-excision and additional biopsy rates, as well as time to surgery.

Methods/Materials: This single-institution, retrospective study included 377 patients treated between 2014 and 2024 who underwent preoperative MRI for localized invasive breast cancer or DCIS. Patients receiving neoadjuvant therapy were excluded. Tumor size concordance with pathology was evaluated using intra-class correlation coefficients (ICC) and Bland–Altman plots. Post-MRI biopsy rates, time from diagnosis to surgery, and re-excision rates were analyzed.

Results: MRI showed moderate reliability with pathology (ICC = 0.70), compared to poor reliability for ultrasound (ICC = 0.12) and mammography (ICC = 0.18). Reliability was higher for invasive tumors (ICC = 0.74) than for pure DCIS (ICC = 0.48), and greatest for invasive-only tumors (ICC = 0.83). MRI prompted 43 (11.4%) additional biopsies, 17 (39.5%) of which changed surgical management, while keeping median time to surgery from original diagnosis under 60 days (43 days). Re-excision for positive margins occurred in 53 (14.0%) patients, below national benchmarks.

Conclusions: Preoperative MRI demonstrated superior concordance with pathology and improved surgical planning, especially for invasive cancers. Although it increased biopsy rates, a substantial proportion of findings altered management without lengthening time to surgery, supporting selective MRI use in preoperative workflows.