Background: The steady increase in colorectal cancer (CRC) could be reversed through timely secondary prevention (screening) as a main strategy. The aims of this study were to determine the main features of CRC, survival rate and related factors for different types of identified CRCs in a population-based screening programme using the faecal immunochemical test (FIT).
Materials and methods: The CRCs in the susceptible population to be screened between 2009 and 2014 were identified and classified into four groups: (a) nonscreening-detected CRC (diagnosed before first screening invitation and nonparticipants), (b) screening-detected CRC, (c) interval cancer (IC) FIT (diagnosed between screening rounds after a negative FIT) and (d) IC colonoscopy (diagnosed before the colonoscopy surveillance, which is recommended after the screening colonoscopy). Patient demographics and epidemiological characteristics, tumour characteristics and survival were compared between the four groups.
Results: 5909 individuals were diagnosed with a CRC. The median follow-up of survival was 4.6 years (range: 0-9 years). The study highlights a significant difference (P<0.0001) in the 5-year survival in the screening-detected CRC group compared with those who had nonscreening-detected CRCs (90.1 vs. 66.7%). Although ICs are not desirable events, the 5-year survival rate is significantly higher with respect to nonparticipants (P<0.0001) (76.3 vs. 60.5%), this being the group with the lowest survival rate.
Conclusion: The significantly higher 5-year survival rate of 23.4% of the participants in the screening programme suggests that incidence and mortality rates of CRC will decrease in the near future for participants in screening programmes. A high participation rate is essential to achieve health benefits, irrespective of the type of participation.