Comparison of Direct Digital Mammography, Computed Radiography, and Film-Screen in the French National Breast Cancer Screening Program

Abstract

The purpose of this article was to compare the performance of digital mammography using hardcopy image reading against film-screen mammography in a French national routine population-based screening program with a decentralized organization. The French context offered the opportunity to examine separately computed radiography and direct digital mammography performances in a large cohort. The study includes 23,423 direct digital mammography, 73,320 computed radiography, and 65,514 film-screen mammography examinations performed by 123 facilities in Bouches du Rhône, France, for women 50-74 years old between 2008 and 2010. We compared abnormal mammography findings rate, cancer detection rate, and tumor characteristics among the technologies. Abnormal finding rates were higher for direct digital mammography (7.78% vs 6.11% for film-screen mammography and 5.34% for computed radiography), particularly in younger women and in denser breasts. Cancer detection rates were also higher for direct digital mammography (0.71% vs 0.66% for film-screen mammography and 0.55% for computed radiography). The contrast between detection rates was stronger for ductal carcinoma in situ. Breast density was the main factor explaining the differences in detection rates. For direct digital mammography only, the detection rate was clearly higher in dense breasts whatever the age (odds ratio, 2.20). Except for grade, no differences were recorded concerning tumor characteristics in which the proportion of high-grade tumors was larger for direct digital mammography for invasive and in situ tumors. Direct digital mammography has a higher detection rate than film-screen mammography in dense breasts and for tumors of high grade. This latter association warrants further study to measure the impact of technology on efficacy of screening. The data indicate that computed radiography detects fewer tumors than film-screen mammography in most instances.