# Roll out AI-supported mammography nationally as a stepped-wedge trial

Source: https://onco.cc/ideas/idea-prev-mammography-ai-stepped-wedge/  
OnCo record `idea-prev-mammography-ai-stepped-wedge` (Idea). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Sweden's MASAI trial showed AI can safely replace one of two radiologists. Rolling it out region by region in a randomised order would prove it works at national scale and that interval cancers do not rise.

## Summary

MASAI (Lund) demonstrated a 44% workload reduction and higher cancer detection with AI-supported reading. Rather than piecemeal adoption, propose national programmes adopt in a randomised stepped-wedge order so every region serves as its own control, with interval cancer rate and recall rate as co-primary endpoints.

## Fields

- Kind: Idea
- Last checked: 2026-09-08
- Hypothesis: National AI-supported reading reduces radiologist reading load by at least 40% with no increase in interval cancers and no increase in DCIS-only detection.
- Rationale: Stepped-wedge gives regulator-grade evidence at the cost of an implementation programme, and detects harms (recall, DCIS inflation) that single-centre trials cannot.
- Proposed test: Run a three-year stepped-wedge across about ten regions of a national programme with a pre-registered analysis.
- Maturity: being-tested-at-scale
- Actor: policy

## Sources

- Bottleneck evidence (The hardest cancers are found late): Crosby et al., Early detection of cancer (Science 2022): https://doi.org/10.1126/science.aay9040

## Connected records

- cancers: [HR-positive / HER2-negative breast cancer](https://onco.cc/cancers/breast-hr-positive/)
- fronts: [Early Detection & Screening](https://onco.cc/fronts/early-detection/), [Imaging](https://onco.cc/fronts/imaging/)
- technologies: [AI in radiology](https://onco.cc/technologies/radiology-ai-screening/), [Mammography & tomosynthesis](https://onco.cc/technologies/mammography/)
- companies: [Lunit](https://onco.cc/companies/lunit/)
- bottlenecks: [Not enough oncologists, nurses, pathologists, physicists](https://onco.cc/bottlenecks/b-workforce/), [The hardest cancers are found late](https://onco.cc/bottlenecks/b-early-detection/)
- key papers: [Early detection of cancer](https://onco.cc/key-papers/paper-crosby-science/), [MASAI: AI-supported mammography screening finds more cancers with half the radiologist workload](https://onco.cc/key-papers/paper-masai-lancet-oncol-2023/)

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