double reading

Mammography screening looks for breast cancer in women who have no symptoms, so the reading of the images is the whole of the test. One reader misses some cancers. Organised programmes across Europe answer that by having every screening mammogram examined independently by two readers, usually radiologists, with a consensus discussion or a third opinion to settle the cases where the two disagree. That is double reading, and the investigators who ran the MASAI trial inside Sweden's national programme describe it as the standard of care in European screening programmes.

The practice costs people. Doubling the reading means a service needs twice the radiologist time for every woman screened, in a specialty many countries cannot staff. That is why trials of artificial intelligence in screening are usually judged on two measures at once: how many cancers a programme finds, and how many readings it takes to find them. The European Commission Initiative on Breast Cancer issued a conditional recommendation in July 2023, resting on very low certainty evidence, suggesting double reading supported by artificial intelligence over double reading without it.