Screening Breast MR Imaging in Women with a History of Lobular Carcinoma in Situ

Abstract

To assess the utility of screening magnetic resonance (MR) imaging in the detection of otherwise occult breast cancers in women with a history of lobular carcinoma in situ (LCIS). This HIPAA-compliant study received institutional review board approval. The need for informed consent was waived. Retrospective review of the database yielded 670 screening breast MR studies obtained between January 2003 and September 2008 in 220 women with a history of LCIS. MR and mammographic findings were reviewed. Number of cancers diagnosed, method of detection, and tumor characteristics were examined. The cumulative incidence of developing breast cancer as detected with MR imaging and mammography was calculated. Breast density was examined as a prognostic factor in the cumulative incidence analysis. Biopsy was recommended in 63 lesions seen in 58 (9%) of 670 screening MR studies. Eight additional lesions were identified at short-term follow-up MR imaging for a total of 71 lesions in 59 patients. Twelve cancers (20%) were identified in 60 lesions sampled. Biopsy was recommended in 26 additional lesions identified at mammography; biopsy was performed in 25 of these lesions and revealed malignancy in five (20%). Overall, 17 cancers were detected in 14 patients during the study period. Of these, 12 were detected with MR imaging alone, and five were detected with mammography alone. Of the 12 cancers detected at MR imaging, there were nine invasive cancers and three cases of ductal carcinoma in situ (DCIS). Of the five cancers detected at mammography, two were invasive and three were DCIS. MR imaging is a useful adjunct modality with which to screen women with a history of LCIS at high-risk of developing breast cancer, resulting in a 4.5% incremental cancer detection rate. Sensitivity in the detection of breast cancers with a combination of MR imaging and mammography was higher than sensitivity of either modality alone.