CAD correctly identified 157 of the 200 cancers, a sensitivity of 79%. Sensitivity was suggestively but nonsignificantly lower with increased density (P = 0.09). In those cancer cases with density at or below the median of 20%, sensitivity was 82%, compared with 75% in those with density above the median. The presence of one or more false CAD prompts was suggestively but not significantly more likely in controls than cases (87% vs. 80%, P = 0.06). The number of false prompts was significantly higher in controls (average 3.6 vs. 2.6, P <0.001). False prompts were significantly less likely with higher density (P = 0.008). False prompts were present in 86% of cases and controls with density at or below the median, and in 81% of those with density above the median.