A 21-year study of nearly 2.2 million people found colorectal cancer mortality in Basque residents aged 50 to 69 fell from 39.7 to 19.8 per 100,000 after FIT screening was introduced.
2012 marked the turning point—three years after the program began—supporting a link between biennial faecal immunochemical testing and the sustained drop in deaths through 2024.
The program detected 4,892 colorectal cancers, with 70.8% found at stages I or II, when treatment is less aggressive and chances of cure are much higher.
Researchers estimate mortality in the screened age group would have been 46.2% higher without the program, though they said the observational study cannot prove causation as firmly as a clinical trial.