Systematic review of agreement between tomosynthesis and pathologic tumor size for newly diagnosed breast cancer and comparison with other imaging tests.

INTRODUCTION: Tomosynthesis is proposed to improve breast cancer assessment and staging as a complementary role to its detection capability. We examine the accuracy of tomosynthesis in measuring tumor size relative to pathology and compared with other tests. Areas covered: A systematic literature search identified studies of tomosynthesis in estimating the size of newly diagnosed breast cancers. Descriptive analyses were performed due to heterogeneity in patients, technology, and methods between studies. Eight studies were eligible (678 patients). Mean differences (MDs) between measurements (tomosynthesis-pathology) were generally small; overestimation (MDs of 1-3 mm) and underestimation (-1 mm) were reported. Limits of agreement (LOA) ranged between ±10 mm and ±28 mm. MDs did not differ in high and low breast densities. Large underestimation (-11 mm) and wide LOA (±41 mm) were reported for invasive lobular carcinoma. MDs and LOA were lower for tomosynthesis than mammography, but differences between tests were small. Expert commentary: Although tomosynthesis is a promising technology for assessing breast cancer size, few studies in that context had limitations (small sample sizes, heterogeneous populations, and technologies). Studies using current technology and appropriate statistical methods are required to establish the magnitude of improvement in measurement accuracy, and patients for whom the test may be of most benefit.