A randomised screening trial reports what AI-supported mammography actually changes
Sweden's MASAI trial randomised over 100,000 women between AI-supported single reading and standard double reading. A clinical safety analysis appeared in The Lancet Oncology in 2023; the cancer-detection analysis reported a 29% higher screen-detected cancer detection rate and a 44.2% reduction in screen-reading workload — 48,444 fewer readings — with seven more false positives between the arms; and the full results in The Lancet reported a non-inferior interval-cancer rate, higher sensitivity, unchanged specificity, and fewer interval cancers with unfavourable characteristics. This is the strongest human-consequence evidence in the pack, and it is worth noting how much it cost to obtain: a population-scale randomised trial running for years, in one country, for one modality.
Observed — measured or witnessed, with the observation cited.
Subjects
- Machine learning in medical imaging · technology · not located
Evidence
Partly verified — Core facts are sourced; some optional detail is deliberately absent.
The MASAI trial — AI-supported mammography screening, randomised controlled evidence
MASAI is a randomised, controlled, non-inferiority, single-blinded, population-based screening trial in Sweden enrolling over 100,000 women. Reported results include a 29% higher screen-detected cancer detection rate with AI support, a 44.2% reduction in screen-reading workload (48,444 fewer readings), false-positive counts of 772 (1.5%) in the intervention arm against 765 (1.4%) in the control arm, and in the full results a non-inferior interval-cancer rate reported as about 12% lower, higher sensitivity, unchanged specificity and fewer interval cancers with unfavourable characteristics. V55 verification basis: none of the three papers was fetched — thelancet.com and sciencedirect.com are blocked to this session. The figures and the trial design were carried in search results attributing them to the named Lancet titles and to institutional press material about them; the publication dates of the final results are reported variously as late 2025 and early 2026 and were NOT resolved, and no DOI is asserted.
The Lancet; The Lancet Digital Health; The Lancet Oncology (Elsevier) · 2023 to 2026 · Partly verified
Lång, K. et al., "Artificial intelligence-supported screen reading versus standard double reading in the Mammography Screening with Artificial Intelligence trial (MASAI): a clinical safety analysis…", The Lancet Oncology (2023); the MASAI cancer-detection analysis in The Lancet Digital Health (2025); "Interval cancer, sensitivity, and specificity comparing AI-supported mammography screening with standard double reading without AI in the MASAI study", The Lancet, article PIIS0140-6736(25)02464-X