Access to prior screening mammograms affects the specificity but not sensitivity of radiologists' performance.

Aims: To establish the impact that access to prior mammograms has on radiologists' performance and the influence of radiologists' characteristics and breast density on their subsequent performance.

Methods: Eight participants independently interpreted 72 digital screening mammograms in two reading sessions using the Royal Australian and New Zealand College of Radiologist's classification. In the first reading session, participants were given access to current and prior mammograms. In the second reading session six months later, participants only had access to the current mammograms. Radiologists' specificity, sensitivity, lesion sensitivity, Receiver Operating Characteristic (ROC) curve, and Jacknife Alternative Free-response ROC (JAFROC) were calculated. A Paired T-test was used to compare readings with and without prior mammograms, and to assess if breast density influenced participants performance. Independent Sample T-test was used to compare performance across radiologists' characteristics. A relative risk analysis was conducted to assess the probability of false positives and false negatives when prior mammograms were available.

Results: Access to prior mammograms improved specificity in dense and non-dense breasts (p≤0.01) and reduced false positives (p = 0.01) but had no effect on sensitivity (p = 0.37), lesion sensitivity (p = 0.67), ROC (p = 0.16), and JAFROC (p = 0.24). Prior mammogram also reduced the probability of false positives (RR = 0.38; 95%CI:0.26-0.57, p<0.0001) without affecting the false negative rate (RR = 1.14; 95%CI:0.88-1.49, p = 0.30). The impact of prior mammograms on performance was not influenced by breast density or radiologists' characteristics.

Conclusions: Access to prior mammograms improves radiologists' specificity and reduces false positives without affecting sensitivity and the false negative rate regardless of radiologists' characteristics and breast density.