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.