Breast MRI after bilateral mastectomy: is it indicated?

Little is known about the use of breast MRI as a diagnostic or surveillance tool in patients after bilateral mastectomy. The objective of this study was to evaluate breast MRI after bilateral mastectomy. Participants consisted of 48 women with prior bilateral mastectomy who underwent breast MRI between 2003 and 2009. Seventy-nine breast MRIs were obtained. The median time between mastectomy and first MRI was 36 months. MRI was ordered most often by a medical oncologist (71%). Median age at bilateral mastectomy was 49 years (range, 33 to 72 years). Reasons for obtaining MRI included surveillance in 60 (76%), mass in eight (10%), lymph nodes in four (5%), pain in three (4%), and abscess in one (1%). Overall, 68 (86%) MRIs showed benign imaging findings only. Within the surveillance group, six patients had MRIs with findings that changed management; four patients had some residual breast tissue, and two patients had findings outside the breast that were better evaluated by CT or bone scan and were ultimately benign. MRI confirmed locoregional recurrence in two patients with highly suspicious physical findings. Overall, postmastectomy breast MRI had limited use, finding no unsuspected recurrences within our study group. Although MRI can be helpful to establish the presence of residual breast tissue after bilateral mastectomy, subsequent routine screening breast MRI should be questioned if no residual breast tissue is identified.