MRI Better for Screening Genetically High-Risk Women For Breast Cancer

A recent study was conducted to compare performance of mammography, MRI, and ultrasound (US) in cancer detection in genetically high-risk women.

It was found that MRI is better for screening genetically high-risk women.

Design/Participants
A prospective multi-institutional study including 171 asymptomatic high-risk women who were either BRCA1/BRCA2 carriers or having at least a 20% probability of carrying these genetic mutations.

Methodology
Mammography, US, and MRI were performed in all participants. Separate radiologists reviewed each imaging study and all suspicious lesions were biopsied. Recall rate, biopsy rate, positive predictive value, and cancer yield were evaluated for each imaging modality.

Results
6 invasive ductal carcinomas were detected during the study period. Mammography detected 33% of cancers and ultrasound detected 17%. However, MRI detected all 6 cancers.

Cancers not detected on either mammography or US, but detected on MRI, occurred in either heterogeneously or extremely dense parenchyma backgrounds. Recall rate and biopsy rate of MRI was higher compared to both mammography and US.

The positive predictive value (PPV) of biopsies for MRI-detected lesions was 43% and 50% for mammography. The PPV for US-detected lesions was only 25%. Overall, the cancer yield for all 3 modalities was 3.5%.

Conclusions
Screening MRI has the highest recall rate, biopsy rate, PPV, and cancer detection rate among the 3 screening modalities.

Reviewer’s Comments
Previous studies have suggested that mammography alone may not be sufficient for screening genetically high-risk women, such as BRCA1/BRCA 2 carriers.

The current American Cancer Society (ACS) guidelines for screening MRI include high-risk women with an approximately 20% to 25% or greater lifetime risk of breast cancer, including carriers of BRCA1/BRCA2, women with a strong family history of breast or ovarian cancer, and women who have had radiation therapy for Hodgkin’s disease.

Although this study has some limitations such as small study size and lack of long-term follow up, the results support the current ACS guidelines.

Author: Bokran Won, MD

Reference:
Cancer Yield of Mammography, MR, and US in High-Risk Women: Prospective Multi-Institution Breast Cancer Screening Study.