Organised Colorectal Cancer Screening and Changes in Mortality and Incidence Trends: A Population-Based Study

Area of Science:

• Public Health
• Oncology
• Epidemiology

Background:

• Organised colorectal cancer (CRC) screening programmes are common in Europe, but real-world effectiveness data, especially for faecal immunochemical testing (FIT)-based programmes, is limited.
• The Galician CRC screening programme was implemented progressively from 2013 to 2019.

Purpose of the Study:

• To evaluate the population-level effectiveness of the Galician FIT-based CRC screening programme.
• To analyse changes in CRC mortality and incidence rates before and after programme implementation.

Main Methods:

• Ecological time-series study using data from the Galician Tumour Registry (2015-2023).
• Analysis of age-standardised mortality (ASMR) and incidence (ASIR) rates using the European Standard Population (ESP2013).
• Interrupted time-series (ITS) models to assess structural changes (ΔAPC) in mortality and incidence trends.

Main Results:

• Overall CRC mortality showed a significant decline (APC -3.00%) between 2015-2023, with a marked shift from an increasing to a decreasing trend post-implementation (ΔAPC -17.32).
• In the 50-69 age group, mortality decreased by -8.08% annually post-implementation (ΔAPC -19.88), and incidence also showed a significant structural modification (ΔAPC -25.06).
• ASMR decreased by 14.33% and ASIR by 13.42% between 2015-2017 and 2019-2023, with larger reductions in the 50-69 age group and for colon cancer.

Conclusions:

• The implementation of an organised FIT-based CRC screening programme was associated with significant structural changes in CRC mortality and incidence trends.
• The screening programme demonstrated particular effectiveness in reducing CRC mortality and incidence among individuals aged 50-69 years.