Marinovich ML, et al. - Tomosynthesis was compared with mammography in estimating the size of newly-diagnosed breast cancers. Two independent readers retrospectively measured all pathologically-confirmed cancers detected in the STORM-2 trial (90 cancers, 85 women) on tomosynthesis and one reader measured cancers on mammography, in addition. Relative to mammography, tomosynthesis overestimated tumor size in women with dense breasts. In the low-density subgroup, there was low average bias for both tests. Large variability in measurements was observed for cancers detected only by tomosynthesis.