Clinical and social impact of the COVID-19 pandemic on colorectal cancer screening programs in Spain

Abstract Colorectal cancer (CRC) is a leading cause of cancer-related mortality and the second most frequently diagnosed in Spain. In line with EU recommendations, Spanish CRC screening programmes (CRCSP) invite individuals aged 50–69 years to biennial faecal occult blood testing, followed by colonoscopy if indicated. However, the impact of COVID-19 on CRCSP performance remains insufficiently characterised. This study analysed key performance indicators and screening duration across three Spanish CRCSPs (n = 2,101,865) from 2019–2021. Multinomial regression assessed lesion risk by demographic and screening characteristics, while Kaplan–Meier curves evaluated cumulative detection probability by screening delay. Barriers and facilitators to participation were explored via a telephone survey (n = 1073). In 2020, screening invitations decreased by 38% compared with 2019, alongside a proportional reduction in advanced lesion detection. Older age, male sex, first-time invitation, and irregular participation were independently associated with a higher probability of advanced lesions. Screening delays increased, and an 11-month delay to invitation was associated with a higher cumulative probability of detecting advanced lesions, particularly in older (p < 0.001) and male (p < 0.001) individuals. Participation was positively associated with prior COVID-19 infection, greater programme knowledge, and absence of negative perceptions. These findings highlight the need to minimise delays and strengthen engagement strategies, particularly among high-risk groups.