A study may only be feasible when routinely collected data (RCD) are used to identify participants. RCD from one centre in a retrospective study of computer-aided detection (CAD) in breast screening are considered. Double-read mammograms were re-read by a different reader using CAD (R2 ImageChecker®) and the cancer detection and recall rates were compared.
Subjects attended routine screening during 1996 and were aged 50 years or over. Among RCD subjects, 11,947 (92.5%) were eligible. From the study sample (n = 5037), a subsample of 650 (13%) subjects was examined.
Previous attendance was incorrect in all four subjects with earlier screening at a different centre. The reader was correctly recorded in all but one subject where it was missing on the paper copy. Whether a subject was recalled for further examination was correct for all subjects; however, single-reader recall, when recall was requested by only one radiologist, was incorrect in 22 (3%) cases; each was among the 53 (8%) recalls showing 42% were incorrect (95% confidence interval, 28–56%).
Single-reader recall was unreliable and previous attendance did not have sufficient detail to report the whether a screen was prevalent. Both were checked throughout the study. Issues raised when using RCD are discussed.
McGee, M., Gilbert, F., Duffy, S. et al. Quality assurance of routinely collected data in the Computer Aided Detection Evaluation Trial.
Breast Cancer Res6
(Suppl 1), P77 (2004). https://doi.org/10.1186/bcr896