Urban density differences in colorectal cancer screening participation and screening yield in The Netherlands.

Lower socioeconomic status has been associated with higher colorectal cancer incidence and lower participation in population-based screening with faecal immunochemical testing (FIT) but regional variations in participation may also exist. We analysed differences in participation and yield in colorectal cancer screening by urban density level. Data of all invitees to the Dutch colorectal cancer screening programme in 2014-2015 were included. Primary outcomes were participation (returning FIT), FIT positive predictive value, and screening yield (advanced neoplasia detected in invitees). Differences were explored across five levels of urban density. In total 1,873,639 screening invitees were included. FIT participation was 77.3% in the lowest versus 62.8% in the highest urban areas (RR 1.23; 95%CI 1.23-1.24). FIT positive predictive value was 58.6% in the lowest versus 55.2% in the highest urban areas (RR 1.06; 95% CI 1.04-1.09). Screening yield was also higher in the lowest (2.1%-2.3%) compared to the highest urban areas (1.8%). Compared to socioeconomic status, differences in urban density were associated with larger differences in screening participation. In conclusion, participation is lower and fewer cases of advanced neoplasia are detected in areas with a high urban density in the Dutch colorectal cancer screening programme. Differences in urban density could be used in tailoring regional strategies to target barriers in colorectal cancer screening.