From the Journals

Abbreviated MRI bests digital breast tomosynthesis in finding cancer in dense breasts



For women with dense breasts, abbreviated magnetic resonance imaging was more effective than was digital breast tomosynthesis for detecting invasive breast cancer in a cross-sectional study of 1,444 women who underwent both procedures.

Dense breasts are a common reason for failed early diagnosis of breast cancer, wrote Christopher E. Comstock, MD, of Memorial Sloan Kettering Cancer Center, New York, and colleagues. Digital breast tomosynthesis (DBT) and abbreviated breast magnetic resonance imaging (MRI) are becoming more popular as safe and cost-effective breast cancer screening options, but their effectiveness in women with dense breasts and average breast cancer risk has not been compared.

The researchers reviewed data from 1,444 women aged 40-75 years at 47 institutions in the United States and 1 in Germany. The women underwent both DBT and MRI. The primary endpoint was the detection of invasive cancers, of which 17 were identified at baseline screening. Abbreviated breast MRI detected all 17 cases of invasive cancer, compared with 7 detected by DBT. In addition, MRI detected six of seven women with ductal carcinoma in situ, while DBT identified two of the seven cases, according to the study, which was published in JAMA.

Overall, the invasive cancer detection rate was 11.8 per 1,000 women for MRI compared with 4.8 per 1,000 women for DBT. Sensitivity for MRI and DBT was 96% vs. 39%, and specificity was 87% vs. 97%.

The rate of recommendation for further screening was not significantly different between the procedures (8% for MRI and 10% for DBT). The most common adverse events were three cases of mild allergic reactions and two cases of anxiety.

The study findings were limited by several factors including the inability to show an association between abbreviated breast MRI and breast cancer mortality and the lack of cost-effectiveness comparisons for the two procedures. Because eligibility criteria required a prior breast mammogram to see if the breasts were dense, the study compared an incidence DBT screen to a prevalence abbreviated MRI screen, Dr. Comstock and associates noted.

However, the results show a significantly increased breast cancer detection rate with abbreviated MRI, which merits additional research to examine the relationship between screening strategies and clinical outcomes for women with dense breasts, they said.

The study was supported in part by the National Cancer Institute of the National Institutes of Health, and by Bracco Diagnostics through funding to the ECOG-ACRIN Cancer Research Group. Dr. Comstock disclosed financial relationships with Bracco Diagnostics and Bayer, and three coauthors disclosed financial relationships with other imaging companies. The remaining coauthors had no relevant financial disclosures.

SOURCE: Comstock CK et al. JAMA. 2020 Feb 25. doi: 10.1001/jama.2020.0572.

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