PCORI has identified the need for large studies that look at real-life questions faced by diverse patients, caregivers, and clinicians. To address this need, PCORI launched the Pragmatic Clinical Studies initiative in 2014. Pragmatic clinical studies allow for larger-scale studies with longer timelines to compare the benefits and harms of two or more approaches known to be effective for preventing, diagnosing, treating, or managing a disease or symptom. They focus on everyday care for a wide range of patients. This research project is one of the studies PCORI awarded as part of this program.

This research project is in progress. PCORI will post the research findings on this page within 90 days after the results are final.

What is the research about?

In the United States, 27.6 million women ages 40-74 have dense breasts. Dense breasts have less fatty tissue and more nonfatty tissue than nondense breasts. Women who have dense breasts have an increased risk for breast cancer. These women also have an increased risk that a mammogram will miss cancer.

Doctors use three imaging tests to look for breast cancer: mammograms, tomosynthesis, and magnetic resonance imaging (MRI). Often, doctors use MRI and/or tomosynthesis, a type of 3D x-ray, in addition to mammograms for breast cancer screening or diagnosis. For example, a doctor may order an MRI after a mammogram to see where the cancer is located in the breast before doing surgery.

In this study, the research team wants to know whether women with dense or nondense breasts should get tomosynthesis or MRI in addition to mammograms when getting screened for breast cancer. The team also wants to know if having an MRI after a new cancer diagnosis and before surgery benefits women with dense or nondense breasts.

Who can this research help?

Findings from this study may help women and their doctors weigh the benefits and harms of breast cancer screening with or without follow-up tests and decide which approach to use. The findings may also help policy makers write breast cancer screening guidelines.

What is the research team doing?

The research team is collecting information from six breast imaging registries from 2005 to 2017. These registries collect information such as whether or not women have dense breasts or have been diagnosed with breast cancer. Women join the study after they get a breast imaging test at a clinic that is part of one of the registries.

The study has two parts. In the first part, the research team is comparing three screening approaches for women with dense or nondense breasts:

• mammography alone
• mammography plus tomosynthesis
• mammography plus MRI

The team is looking at how often breast imaging tests correctly find cancer. The team is also looking at screening harms, such as how often women have a breast biopsy when they do not have breast cancer.

In the second part of the study, the research team is comparing mammography alone versus mammography plus MRI for women with dense or nondense breasts who will have breast cancer surgery. The team wants to know if a breast MRI before surgery helps doctors find and remove all the cancer, or if the MRI leads to more biopsies and treatment without the benefit of the cancer being less likely to come back.

Cancer advocacy groups, insurers, doctors, and patients are helping to design the study and identify which questions are most important to patients.

Research methods at a glance