Prior mammogram review may affect the performance of radiology trainees in identifying breast cancers and normal cases

Objectives: To study the effect on radiology trainees' observer performance through the availability of prior screening mammograms as part of seven unique education test sets. Methods: Australian radiology trainees (n=150) completed 469 readings of seven educational test sets (each set with 60 cases, 40 normal and 20 cancer cases). The percentage of cases with a prior screening mammogram was 68.7%. Mammographic density (MD) evaluated via BIRADS was spread across the test sets, with 40.5% having 25-50% glandular tissue (BIRADS "B"), 37.4% of cases having 50-75% or "C", 12.6% have a >75% MD and 9.5% having the lowest MD rating "A". Trainees were asked to score the cases on a scale of 1 (normal), 2 (benign), 3 (equivocal findings), 4 (suspicious finding) and 5 (highly suggestive malignancy). Mann-Whitney U was used to compare the specificity and sensitivity of radiology trainees among cases with and without prior images. Results: Radiology trainees had significantly higher sensitivity across all MD levels when prior images were not available (A-B, P=0.006; C-D, P=0.027). Specificity was also significantly higher for cases of high (C-D) MD without prior images compared with priors available by trainees who read less than 20 cases per week (P=0.008). Conclusions: In a simulated environment, radiology trainees achieved better results in cases without prior images, especially for those who read less than 20 cases per week. The utility of prior case inclusion when providing education and training in reading screening mammograms needs to be revisited, especially for women with high MD.