Digital mammography screening: sensitivity of the programme dependent on breast density.

Abstract

To analyse the impact of breast density on the sensitivity of a population-based digital mammography screening programme (SP) as key evaluation parameter. 25,576 examinations were prospectively stratified from ACR category 1 to 4 for increments of 25% density during independent double reading. SP was calculated as number of screen-detected cancers divided by the sum of screen-detected plus interval cancers (24-months period) per ACR category, related to the first reading (a), second reading (b) and highest stratification if discrepant (c). Chi-square tests were used for comparison. Overall sensitivity of the programme was 79.9%. SP in ACR 4 (a: 50%, b: 50%, c: 50%) was significantly lower than in ACR 3 (a: 72.9%, b: 79.4%, c: 80.7%, p < 0.001), ACR 2 (a: 83.9%, b: 85.7%, c: 83.2%, p < 0.001) and ACR 1 (a: 100%, b: 88.8%, c: 100%; p < 0.001). Frequencies of ACR 4 were a: 5.0%, b: 4.3%, c: 6.9%. Digital mammography screening with independent double reading leads to a high overall SP. In the small group of women with breast density classified as ACR 4 SP is significantly reduced compared to all other ACR categories. • Overall sensitivity of a population-based digital mammography screening programme (SP) was 79.9%. • In women with ACR 1, 2, or 3, SP ranged between 72.9%-100%. • ACR 4 was rare in participants (<7%) and SP was only 50%. • SP in ACR 4 differed significantly from ACR 3 (p < 0.001).