Clinical Management of BRCA Mutation Carriers
These trials appear to establish that MRI is superior to mammography in the detection of hereditary breast cancer, and that women participating in these trials including annual MRI screening were less likely to have a cancer missed by screening. However, mammography identifies some cancers, particularly DCIS, that are not identified by MRI. While MRI does appear to be more sensitive than mammogram, it is unknown whether MRI screening results in a survival benefit or even in downstaging compared with mammography alone. One screening study demonstrated that patients were more likely to be diagnosed with small tumors and node-negative disease than women in two nonrandomized control groups. However, a randomized study of screening with or without MRI using tumor stage or mortality as an endpoint has not been performed. Despite the apparent sensitivity of MRI screening, some women in MRI-based programs will nevertheless develop life-threatening breast cancer. In a prospective study of 51 BRCA1 and 41 BRCA2 mutation carriers screened with yearly mammograms and MRIs (of whom 80 had prophylactic oophorectomy), 11 breast cancers (9 invasive and 2 DCIS) were detected. Six cancers were first detected on MRI, three were first detected by mammogram, and two were interval cancers. All breast cancers occurred in BRCA1 mutation carriers, suggesting a continued high risk of BRCA1-related breast cancer following oophorectomy in the short term. These results suggest that surveillance and prevention strategies may have differing outcomes in BRCA1 and BRCA2 mutation carriers. The American Cancer Society and the National Comprehensive Cancer Network (NCCN) have recommended the use of annual MRI screening for women at hereditary risk for breast cancer.[3,40]
Table 8. Summary of MRI Screening Studies in Women at Hereditary Risk for Breast Cancer
a Based upon the first 1,909 women screened.
b Includes 78 invasive cancers and 19 DCIS (ductal carcinoma in situ) in 94 women.
c Includes 8 patients with invasive cancers and 9 patients with DCIS.
d Includes 11 patients with invasive cancers and 7 patients with DCIS (note that 1 patient reported to have 3 individual DCIS lesions).
e Includes only 75 cancers detected in women who underwent both mammographic and MRI screening.
f Restricted to studies in which ultrasound was performed.
|Series||Rijnsburger ||Warner ||MARIBS ||Kuhl ||Weinstein ||Totals|
|N Patients||Overall||2,157||236||649||687||609||4,338 |
|N Screening Episodes||6,253||457||1,881||1,679||�||10,270|
|N Cancers||Baseline ||22a||13||20||10||0||65|
|Detected at Planned Screening||78||21||33||27||18||177 (80%)|
|N Detected by Each Modality||Mammography||31e||8||14||9||7||69 (35%)|
|Follow-Up ||Median of 4.9 y||Minimum of 1 y||2-7 y||Median of 29.09 mo||2 y||�|