Screening breast magnetic resonance imaging in women with atypia or lobular carcinoma in situ

Background Atypical lesions and lobular carcinoma in situ (LCIS) are associated with an increased risk of breast malignancy. The utility of breast magnetic resonance imaging (MRI) screening in this cohort of women after excision of a high-risk lesion has not been previously established. The objective of this study was to investigate outcomes of breast MRI surveillance in this subgroup of high-risk patients.

Materials and methods We performed a retrospective review of women who required excision of an atypical lesion or LCIS who underwent at least one screening breast MRI from April 2005-December 2011. We collected information on demographics, number of second-look imaging studies recommended, number of biopsies performed and pathologic outcomes.

Results A total of 179 patients met the inclusion criteria, including 131 (73%) with atypical lesions and 48 (27%) with LCIS. Second-look imaging was recommended for 31 of 131 (23.7%) patients with atypical lesions and 8 of 48 (16.7%) with LCIS. Ten biopsies were performed in the atypical cohort (7.6%) with two revealing a malignancy (Positive Predictive Value [PPV] of 20%). In the LCIS cohort, five biopsies were performed (10.4%) with one revealing a malignancy (PPV of 20%).

Conclusions The benefit of breast MRI surveillance in patients after excision of atypical lesions or LCIS has not been clearly delineated previously. Our data demonstrate that the use of screening breast MRI in this cohort results in additional work-up in one-fifth of patients, but a PPV of only 20%. Large, prospective studies would be needed to determine whether breast cancer outcomes differ between patients undergoing conventional breast screening and those undergoing conventional breast screening plus breast MRI surveillance.