Effectiveness of screening women at high risk for breast cancer with alternating mammography and MRI.
Authors: Le-Petross HT , Atchley DP , Whitman GJ , Hortobagyi GN , Arun BK 
Published: December 2010

Abstract #5015

Background&#x2028; MRI has been found to be more sensitive than mammography in the detection of breast cancer, with sensitivity of 71% to 100%, compared to 16 to 40% for mammography. Therefore, MRI has been introduced as an adjunct to annual screening mammography and clinical examination (CE) in women at high risk for developing breast cancer. We investigated the efficacy of alternating screening mammography with MRI every 6 months in women at high risk for developing breast cancer.&#x2028; Methods&#x2028; Retrospective chart review was performed on 334 consecutive women who were seen in the high risk clinic at one institution, from January 1997 to December 2007. Patients with increased risk for breast cancer and had an MRI were included in this study. Women with hereditary breast and ovarian cancer syndrome, personal breast cancer history, a biopsy of atypia or lobular carcinoma in situ (LCIS), or a 20% or higher lifetime risk of developing breast cancer by the Gail model were included. Mammography, ultrasound, and MRI findings were reviewed, along with biopsy results.&#x2028; Results&#x2028; 86 of 334 (26 %) patients underwent annual screening mammography and MRI, with mammography and MRI alternating every six months. The remaining 248 patients underwent prophylactic mastectomies or were treated with chemoprevention. CE was performed every six months. 47% of 86 patients completed the 1st round of MRI surveillance, 32% completed the 2nd round, 15% completed the 3rd round, and 6% completed the 4th round. Of 86 patients who underwent MRI screening, 70 had BRCA mutations, and 16 had a history of breast cancer , a biopsy of atypia or LCIS, or a 20% or higher lifetime risk of developing breast cancer. The median follow-up period was 2 years (range, 1 to 4 years).&#x2028; Nine cancers (6 invasive ductal, 1 invasive lobular, and 2 ductal carcinomas in situ) were detected in 7 of 86 (8.1%) women who underwent screening MRI; two women had bilateral cancers. Among the 9 cancers, 4 (44 %) were identified by MRI but not by mammography, 4 (44 %) were identified by both MRI and mammography, and 1 (11 %) was not identified by mammography or MRI. No cancer was seen by mammography only. Of the 9 tumors, 8 cancers were detected by MRI (sensitivity of 89%). One cancer was identified by mastectomy only (1 mm focus of DCIS). In 4 of the 8 MRI detected-cancers, the mammogram performed six months earlier was normal or demonstrated benign findings. The mean size of the cancers was 10.4 mm (range, 1 to 25 mm). At MRI, 5 cancers appeared as a mass and 3 cancers demonstrated non-mass like enhancement. Metastatic ipsilateral axillary lymphadenopathy was seen in association with 3 of the 9 cancers detected.&#x2028; Conclusions&#x2028; In women at high risk for developing breast cancer, alternating mammography and MRI at six month intervals demonstrated that no cancers were detected by mammography only. Future prospective studies should be performed to evaluate screening with annual mammography and MRI, alternating at six month intervals, versus annual MRI alone.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5015.