Table 3 shows the average reader performance by tumor size for the 45 image sets of patients with invasive cancer. The greatest percentage increase was for cancers 1 cm and under. This is due largely to the relatively poor performance at detecting these cancers with mammography, where only 26% of cases were correctly identified. By adding AWBU, the detection of these small cancers was increased to 65%.
Table 3 Reader performance with 45 invasive cases
≤1 cm >1 to ≤2 cm >2 cm Total
# % # % # % # %
# of cancers 17 100 22 100 6 100 45 100
Mean cancers by mammography 4.4 26 13.5 61 3.0 50 20.9 46
Mean additional cancers by AWBU 6.7 39 6.6 30 2.0 33 15.3 34
Mean total cases detected 11.1 65 20.1 91 5.0 83 36.2 80
% improvement compared to mammography alone 151% 49% 67% 73%
For cases with more than one invasive tumor, the larger of the two was used. For interval cancers after imaging, size is the greatest diameter of the tumor seen retrospectively on the AWBU or mammogram, otherwise the diameter is that reported by pathological diagnosis