Digital Breast Tomosynthesis for the Screening and Diagnosis of Breast Cancer: A Review of the Diagnostic Accuracy, Cost-Effectiveness and Guidelines

Among Canadian women, breast cancer is the most common type of cancer and the second leading cause of death from cancer. As of 2019, it is estimated that approximately 1 in 8 Canadian women develop breast cancer during their lifetime, while around 1 in 33 Canadian women die from breast cancer. Breast cancer most commonly affects women over the age of 40, with the median age at diagnosis 62 years (based on data from the United States).Screening for breast cancer in women aims for early diagnosis of the disease, the possibility of more effective and less invasive treatment, and ultimately improved outcomes. Some women may display symptoms of breast cancer or have suspicious signs when undergoing screening, which may necessitate diagnostic testing., An effective screening or diagnostic technique should demonstrate a positive effect on clinical outcomes (such as mortality) and should not lead to overdiagnosis (e.g. diagnosis and subsequent treatment of cancer would not have caused harm if not treated), or produce high numbers of false-positive results.Canada has had breast cancer screening programs in place since the 1990s. Various techniques may be used for screening and diagnosis of breast cancer. The current standard for screening is digital mammography (DM; also called 2D mammography), which uses X-rays and digital detection. This technique is also used for diagnosis in women with symptoms or suspicious results after a screening mammogram. An emerging technology is digital breast tomosynthesis (DBT; also called 3D digital tomosynthesis). This technique also uses X-ray and digital images; however, it involves taking multiple images from multiple angles to produce 3D images of the breast. It is also possible to obtain synthesized 2D images using DBT. DBT can be used alone or in combination with DM. Screening using DM alone has led to reductions in breast cancer mortality, though there are still concerns related to overdiagnosis and false positive results, as well as high recall rates (the number of women needing follow-up testing after an initial screen).,, The goal of DBT alone or in combination with DM is therefore to improve accuracy of screening and diagnosis, and ultimately lead to improved outcomes for patients, such as reductions in mortality rate and overdiagnosis.The aim of the report is to summarize the clinical utility, diagnostic accuracy, and cost-effectiveness of DBT with or without DM compared to DM alone, and to summarize existing guidelines on this topic. This report is based on a previous CADTH Summary of Abstracts titled “Digital Tomosynthesis for the Screening and Diagnosis of Breast Cancer: Diagnostic Accuracy, Cost-Effectiveness, and Guidelines”.