New suspicious lesions on breast MRI in neoadjuvant therapy not malignant

A total of 419 breast MRI examinations in 297 women (mean patient age, 45 years; range, 32-65 years) were performed to assess response to neoadjuvant treatment. After exclusions, 23 MRI examinations (5.5%) with new suspicious findings distinct from the site of known malignancy comprised the final study cohort. Of these 23 lesions, 13 new suspicious findings (56.5%) were contralateral to the known malignancy, nine (39.1%) were ipsilateral, and one (4.3%) involved the bilateral breasts. Lesion types included mass (16, 69.6%), nonmass enhancement (5, 21.7%), and focus (2, 8.7%).

Noting that, currently, there are no guidelines for the management of new suspicious imaging findings identified on MRI during the course of neoadjuvant systemic breast cancer treatment, "results in this small cohort suggest that these new findings are highly likely to be benign, particularly in the setting of response to therapy, which may potentially obviate biopsies in these patients in the future," wrote Eckstein et al.

"However," the authors of this AJR article concluded, "larger studies across different facilities are needed to confirm whether biopsy may be safely averted in this scenario.