Resumen
Faecal occult blood test interval cancer is one of the potential harms of colorectal cancer screening programmes. These tumours are diagnosed in people who have previously received a negative result in a screening test. The objective of this study was to evaluate interval cancer rates in colorectal cancer screening programmes in Spain, assess their risk factors and compare the characteristics of screen-detected and interval cancer tumours. Identifying interval cancer rates as well as the associated factors would make it possible to improve screening strategies and identify personal variables related to the occurrence of interval cancer. Furthermore, studying the characteristics that distinguish interval cancers from screen-detected cancers would help us understand the nature of these tumours. These results would help evaluate and improve colorectal cancer screening programmes, increase their quality and minimise interval cancer in such programmes.