Based on seven systematic reviews of nonrandomized studies, digital breast tomosynthesis in combination with digital mammography may improve detection rate and recall rate of breast cancer compared to digital mammography alone for screening, though there was heterogeneity in evidence with respect to the type of cancer (invasive versus noninvasive) and screening setting (frequency of screening, number of reads). Results were conflicting in the two eligible randomized controlled trials. Both found no benefit on detection rate for digital breast tomosynthesis in addition to digital mammography for screening, while one randomized controlled trial found benefit for recall rate and the other did not. There was limited evidence in the diagnostic setting. For diagnosis, two systematic reviews provided narrative comparisons of digital breast tomosynthesis alone or in combination with digital mammography to digital mammography alone. Both reported that digital breast tomosynthesis improved sensitivity, though results were conflicting for specificity. One systematic review found that digital breast tomosynthesis alone or in combination with digital mammography improved the detection rate of breast cancer for women with dense breasts in a diagnostic setting. No evidence on the clinical effectiveness or harms of digital breast tomosynthesis was identified. As such, the benefits and harms of digital breast tomosynthesis for screening and diagnosis are unclear. One cost-effectiveness study conducted in the United States found that digital breast tomosynthesis in combination with digital mammography was cost-effective compared to digital mammography alone in women age 40 to 79. Digital breast tomosynthesis and digital mammography was most cost-effective in those age 40 to 49, compared to those age 50 to 59, 60 to 69, and 70 or older. Two guidelines were identified, both of which recommended against using digital breast tomosynthesis for screening of breast cancer in asymptomatic women not at high risk of breast cancer. Recommendations were based on the insufficient evidence for digital breast tomosynthesis on benefits and harms.