Meta-analysis of prospective studies evaluating breast cancer detection and interval cancer rates for digital breast tomosynthesis versus mammography population screening.

INTRODUCTION

Breast cancer (BC) screening using digital breast tomosynthesis (DBT) has been shown to increase cancer detection compared with mammography; however, it is unknown whether DBT impacts interval cancer rate (ICR).

METHODS

We systematically identified prospective DBT studies reporting data on screen-detected and interval BCs to perform a study-level meta-analysis of the comparative effect of DBT on ICR in population screening. Meta-analysis of cancer detection rate (CDR), ICR, and the differences between DBT and mammography in CDR and ICR pooled estimates, included random-effects. Sensitivity analysis examined whether study methods (imaging used, comparison group design, interval BC ascertainment) affected pooled estimates.

RESULTS

Five eligible prospective (non-randomised) studies of DBT population screening reported on 129,969 DBT-screened participants and 227,882 mammography-only screens, including follow-up publications reporting interval BC data. Pooled CDR was 9.03/1000 (95% confidence interval [CI] 8.53-9.56) for DBT, and 5.95/1000 (95% CI 5.65-6.28) for mammography: the pooled difference in CDR was 3.15/1000 (95% CI 2.53-3.77), and was evident for the detection of invasive and in-situ malignancy. Pooled ICR was 1.56/1000 DBT screens (95% CI 1.22-2.00), and 1.75/1000 mammography screens (95% CI 1.46-2.11): the estimated pooled difference in ICR was -0.15/1000 (95% CI -0.59 to 0.29) and was not substantially altered in several sensitivity analyses.

CONCLUSIONS

Meta-analysis shows consistent evidence that DBT significantly increased CDR compared with mammography screening; however, there was little difference between DBT and mammography in pooled ICR. This could suggest, but does not demonstrate, some over-detection. Meta-analysis using individual participant data, randomised trials and comparative studies quantifying cumulative detection and ICR over repeat DBT screen-rounds would provide valuable evidence to inform screening programs.