Lymph Node Positivity: Indication for Preoperative MRI?

Background: The purpose was to determine what factors help predict benefit from preoperative MRI. Methods: We conducted an IRB approved retrospective review of patients with breast cancer who underwent preoperative MRI (2018–2021). Patients were divided into a cohort of no new disease detected on MRI versus new disease detected. Results: Of 420 patients with a new diagnosis of breast cancer who underwent preoperative MRI, 17% had new multicentric, multifocal, or contralateral disease detected. There was no difference between the two cohorts for age (p = 0.23), race (p = 0.45), family history (p = 0.47), breast density (p = 0.14), or hormone status (p = 0.90). In multivariate analysis, age (p = 0.61, OR 0.99), race (p = 0.58, OR 1.26), family history (p = 0.54, OR 0.82), breast density (p = 0.83, OR 0.87), grade (p = 0.87, OR 1.09), tumor size (p = 0.37, OR 0.92), and use of neoadjuvant therapy (p = 0.41, OR 0.72) were not predictive of detection of additional new disease. Presence of positive nodes on ultrasound or mammogram was associated with new or multifocal disease on MRI (p = 0.0005, OR 3.48). Pre-MRI positive nodes increased the likelihood of detection of new disease (p = 0.0002, OR 3.04). Preoperative MRI resulted in more extensive surgery than indicated for 22.2% of the no new disease detected cohort and 6.9% of the new multicentric disease cohort (p < 0.001). Conclusions: Patients with nodal disease detected in their evaluation are more likely to have new multifocal, multicentric, or contralateral disease detected on MRI. The use of preoperative MRI may be particularly helpful in patients with node-positive disease in identifying additional disease that would alter surgical management.