Implementation of Digital Mammography in a Population-based Breast Cancer Screening Program: Effect of Screening Round on Recall Rate and Cancer Detection

Purpose: To compare the effect of the introduction of digital mammography on the recall rate, detection rate, false-positive rate, and rates of invasive procedures performed in the first and successive rounds of a population-based breast cancer screening program with double reading in Barcelona, Spain. Materials and Methods: The study was approved by the ethics committee; informed consent was not required. Data were compared from 12 958 women aged 50-69 years old who participated in a screening round before the introduction of digital mammography (screen-film mammography group) with data from 6074 women who participated in another screening round after the introduction of digital mammography ( digital mammography group). Groups were compared for recall rate and detection rate stratified according to first or successive screening rounds, and logistic regression analysis was performed. Results: Overall recall rates for screen-film and digital mammography groups were 5.5% and 4.2%, respectively (P < .001). The recall rate was higher in the first screening round (11.5% and 11.1% in the screen-film mammography and digital mammography groups, respectively; P = .68) than in successive screening rounds (3.6% and 2.4% in the screen-film mammography and digital mammography groups, respectively; P < .001). The main factors related to the risk of recall were screen-film mammography group ( odds ratio = 1.28), first screening round (odds ratio = 3.53), menopausal status (odds ratio = 0.62), and history of personal benign breast disease ( odds ratio = 2.26). No significant differences were found in the cancer detection rate between groups. In the first screening round, this rate was higher in the digital than in the screen- film mammography group (1.1% and 0.4%, respectively; P < .009). The invasive test rate was 2.6% and 1.3% in the screen-film and digital mammography groups, respectively (P < .001) and was lower with digital mammography than with screen- film mammography in both the first and successive screening rounds. Conclusion: Digital mammography may reduce the adverse effects of screening programs if this technique is confirmed to have the same diagnostic accuracy as screen-film mammography.