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ObjectiveTo assess the feasibility and evaluate the performance of a relaunched colorectal cancer (CRC) screening programme with different cut-offs for men and women.DesignPopulation-based registry study.SettingNine municipalities in Finland which started CRC screening with faecal immunochemical test (FIT) in April 2019 with cut-off levels 70 µg Hg/g faeces for men and 25 µg Hg/g faeces for women.ParticipantsMen (n=13 059) and women (n=14 669) aged 60–66 years invited to screening during the first programme year.Outcome measuresParticipation rates, positivity rates, detection rates of CRC and advanced adenoma (AA), and positive predictive values (PPV) of FIT for CRC and AA.ResultsAltogether 21 993 invitees returned stool samples. The participation rate of women (83.4%; 95% CI 82.8 to 84.0) was significantly higher than that of men (74.7%; 95% CI 73.9 to 75.4). The positivity rates were 2.4% (2.2 to 2.7) and 2.8% (2.5 to 3.1), respectively. In total, 37 CRCs and 116 AAs were detected. The detection rates of CRC and AA per 1000 participants were 1.8 (1.1 to 2.9) and 7.2 (5.6 to 9.1) for men and 1.6 (0.9 to 2.4) and 3.8 (2.8 to 5.0) for women. The PPVs per 100 positive tests were 6.6 (4.0 to 10.3) and 25.7 (20.6 to 31.4) for men and 6.4 (3.9 to 9.8) and 15.5 (11.6 to 20.2) for women.ConclusionsThe chosen FIT strategy narrowed the gap in the diagnostic performance between men and women especially in the detection of CRC. The participation rates were excellent. The levels of positivity and detection rates were moderate and need further action. The results indicate that gender-specific protocols can be introduced to organised CRC screening. It is yet to be seen whether they are more effective than a uniform screening protocol.

Screening for colorectal cancer (CRC) has been shown to decrease colorectal cancer mortality in randomized-controlled trials. However, screening may have an adverse impact on an individual's lifestyle. We describe here the design of a repeated survey study on lifestyle and assess response in the survey target population by randomization to CRC screening and demographic factors. The survey study population (n=10271) included Finnish men and women born in 1951 who were randomized for the CRC screening programme in 2011 and received a questionnaire on lifestyle in 2010 and 2012. We assessed responding by randomization to CRC screening, calendar time and demographic factors using the population-averaged Poisson model. Responding to survey was overall similar in 2010 and 2012. Those invited for CRC screening increased responding in time [incidence rate ratio (IRR) 1.06, confidence interval (CI) 1.03-1.09], whereas controls decreased their responding (IRR 0.97, CI 0.94-1.00). Women were more likely to respond than men (IRR 1.17, CI 1.12-1.23). Also, secondary (IRR 1.20, CI 1.13-1.27) and tertiary (IRR 1.31, CI 1.23-1.40) level education increased the response proportion compared with primary-level education. We could reliably assess the effect of CRC screening invitation and demographic factors on survey response. Although invitation to CRC screening increased responding, the self-selection was similar on both survey rounds. Self-selection should be taken into account when generalizing results from survey studies to their target population.

Present study found no unfavourable changes in total lifestyle in the studied age group due to CRC screening. Results are reassuring from the point of view of CRC screening evaluation.