Intensive surveillance with bi-annual dynamic contrast-enhanced magnetic resonance imaging downstages breast cancer in BRCA1 mutation carriers

PURPOSE: To establish a cohort of high-risk women undergoing intensive surveillance for breast cancer. METHODS: We performed dynamic contrast-enhanced magnetic resonance imaging (MRI) every 6 months in conjunction with annual mammography (MG). Eligible participants had a cumulative lifetime breast cancer risk ≥ 20% and/or tested positive for a pathogenic mutation in a known breast cancer susceptibility gene. RESULTS: Between 2004-2016, we prospectively enrolled 295 women, including 157 mutation carriers (75 BRCA1, 61 BRCA2); participants' mean age at entry was 43.3 years. Seventeen cancers were later diagnosed: four ductal carcinoma in situ (DCIS) and thirteen early stage invasive breast cancers. Fifteen cancers occurred in mutation carriers (11 BRCA1, 3 BRCA2, 1 CDH1). Median size of the invasive cancers was 0.61 cm. No patients had lymph node metastasis at time of diagnosis and no interval invasive cancers occurred. The sensitivity of bi-annual MRI alone was 88.2% and annual MG plus bi-annual MRI was 94.1%. The cancer detection rate of bi-annual MRI alone was 0.7% per 100 screening episodes, which is similar to the cancer detection rate of 0.7% per 100 screening episodes for annual MG plus bi-annual MRI. The number of recalls and biopsies needed to detect one cancer by bi-annual MRI were 2.8 and 1.7 in BRCA1 carriers, 12.0 and 8.0 in BRCA2 carriers, and 11.7 and 5.0 in non-BRCA1/2 carriers, respectively. CONCLUSIONS: Bi-annual MRI performed well for early detection of invasive breast cancer in genomically stratified high-risk women. No benefit was associated with annual MG screening plus bi-annual MRI screening.

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