Comparison of Diffusion-Weighted MRI and Mammography Alone or Combined Mammography and Ultrasonography for Screening Women With a Personal History of Breast Cancer (DIMRISC-2 Study)

Women with personal history of breast cancer (PHBC) are at risk of developing second breast cancers in the conserved and contralateral breast. Because early detection of second breast cancers at the asymptomatic phase can improve relative survival by 17-28%, guidelines recommend annual mammography screening in women with PHBC. However, lower sensitivity and higher interval cancer rates are observed in women with a PHBC compared with women without, especially in women 50 years or younger and those with dense breasts. In a multicenter comparison study of 754 women, MRI screening detected 3.8 additional cancers and ultrasonography detected 2.4 additional cancers, and increased sensitivity over mammography alone. However, the use of breast MRI is limited not only by high costs and long examination time but also by high false-positive findings. In addition, the use of intravenous gadolinium-based contrast agent is contraindicated in women with renal impairment or contrast material allergy contrast. Supplemental ultrasonography in patients with PHBC reports lower sensitivity with high interval cancer rate. Thus, there is a need to develop a more safe, accurate, and cost-effective supplemental imaging modality for screening in women with PHBC. Diffusion-weighted (DW) MRI is an unenhanced fast, functional modality that measures the movement of water molecules to create tissue contrast. Breast malignancies exhibit hindered diffusion and appear hyperintense on DW MRI with low apparent diffusion coefficient (ADC) compared to normal surrounding tissue. Multiple studies have shown that the use of DW MRI can significantly reduce the false positives and unnecessary benign biopsy of breast MRI. Several studies have shown that DW MRI has a potential to detect mammography occult breast cancers with less false positives compared to ultrasonography. These observations have led to the consideration of utilizing DW MRI to screen women with PHBC. In Diffusion-weighted MRI for Breast Cancer Screening (DIMRISC-2) study, we hypothesized that the screening performance of high-resolution DW MRI at 3.0 T should be superior to mammography alone or combined mammography and ultrasonography in women with PHBC. In our institution, alternating conventional imaging and DW MRI screening is offered for patients who have undergone breast surgery and at increased risk of an interval second breast cancer.