Can artificial intelligence reduce the interval cancer rate in mammography screening?

Lång K, Hofvind S, Rodríguez-Ruiz A, Andersson I.

European Radiology (2021). https://doi.org/10.1007/s00330-021-07686-3

Aim and Objective
To investigate whether artificial intelligence (AI) can reduce interval cancer in mammography screening.

Materials and Method
Preceding screening mammograms of 429 consecutive women diagnosed with interval cancer in Southern Sweden between 2013 and 2017 were analysed with a deep learning–based AI system (Transpara, ScreenPoint Medical). The system assigns a risk score from 1 to 10. Two experienced breast radiologists reviewed and classified the cases in consensus as true negative, minimal signs or false negative and assessed whether Transpara correctly localised the cancer. The potential reduction of interval cancer was calculated at different risk score thresholds corresponding to approximately 10%, 4% and 1% recall rates.

Results
A statistically significant correlation between interval cancer classification groups and AI risk score was observed (p < .0001). AI scored one in three (143/429) interval cancer with risk score 10, of which 67% (96/143) were either classified as minimal signs or false negative. Of these, 58% (83/143) were correctly located by AI, and could therefore potentially be detected at screening with the aid of AI, resulting in a 19.3% (95% CI 15.9–23.4) reduction of interval cancer. At 4% and 1% recall thresholds, the reduction of interval cancer was 11.2% (95% CI 8.5–14.5) and 4.7% (95% CI 3.0–7.1). The corresponding reduction of interval cancer with grave outcome (women who died or with stage IV disease) at risk score 10 was 23% (8/35; 95% CI 12–39).

Conclusion
The use of Transpara in screen reading has the potential to reduce the rate of interval cancer without supplementary screening modalities.

Key points
– Retrospective study showed that Transpara detected 19% of interval cancer at the preceding screening exam that in addition showed at least minimal signs of malignancy. Importantly, these were correctly localised by Transpara, thus obviating supplementary screening modalities.
– Transpara could potentially reduce a proportion of particularly aggressive interval cancers.
– There was a correlation between AI risk score provided by Transpara and interval cancer classified as true negative, minimal signs or false negative.