MRI screening for breast cancer in women with high familial and genetic risk: First results of the Dutch MRI screening study (MRISC)

English

Reviewer: Walter Sall, MD
OncoLink
Ultima Vez Modificado: 2 de junio del 2003

Presenter: M. Kriege
Presenter's Affiliation: University Medical Center Rotterdam
Type of Session: Plenary

Background

Women at high genetic or familial risk for breast cancer undergo careful surveillance. The value of screening in these women is unknown.
MRI is a newer modality of breast cancer detection with high sensitivity. It may be able to detect tumors, particularly noncalcified tumors, that are missed by conventional mammography.
This trial intended to study the value of regular surveillance and the efficacy of MRI compared to mammography.

Materials and Methods

This is a prospective enrollment study of 1911 women enrolled from 1999-2002. Eligible women had a calculated lifetime breast cancer risk of >15%. Patient age ranged from 25-70.
Surveillance for all women included clinical breast exam every 6 months and both yearly mammography and MRI.

Results

Average patient age was 40. Median follow up was 2.1 years. 41 cancers were detected over a total of 3720 cumulative follow up years during which time 3280 MRIs were performed.
The sensitivity, specificity and PPV of mammography was 43%, 37% and 8.9%. The corresponding values for MRI were 74%, 89% and 6.8%.
Of the diagnosed tumors, 5 were DCIS, 14 were < 1cm, 11 were 1-2cm and 9 were > 2 cm. Only 15% were node positive.

Author's Conclusions

The cancer detection rate was 10.5 per 1000 women years in this high risk population.
The sensitivity for the detection of invasive breast cancer was 83% for MRI and 37% for mammography (p<0.05). However, specificity and PPV were lower for MRI
Mammography continues to be better for detecting DCIS.
The stage of MRI detected tumors is more favorable than those detected by conventional means. This may translate into a survival benefit for MRI screened women at high risk of breast cancer.

Clinical/Scientific Implications

Large patient numbers and careful statistical analysis in this study provides the best evidence yet of the additional benefit of MRI in the early detection of breast cancer in a high risk population. The lower specificity and PPV of MRI indicates that this technique may lead to more false positives and unneccesary biopsies. It is important to keep in mind that this data is not applicable to women of average breast cancer risk. Also, the expense and inconvenience of annual MRI exams in this rather large patient population must be examinied closely before final recommendations regarding MRI screening can be made. Finally, one must remember that access to breast cancer screening with MRI is limited to academic centers with experience in reading these radiologic studies.

Oncolink's ASCO Coverage made possible by an unrestricted Educational Grant from Bristol-Myers Squibb Oncology.