Detection of Colorectal Neoplasia in a Cohort Before and After the Change of Fecal Occult Blood Test in a French Colorectal Cancer Screening Program.

Objective: To estimate the change in the participation rate and the change in neoplasia incidence before and after the change of the Fecal Occult Blood Test (FOBT) in the cohort included in the Colorectal Cancer Screening Program (CRCSP).

Methods: Cohort of 279,210 people, aged 50-74 years, invited at least once before 2009, to participate in a CRCSP campaign. The participation rate and the cumulative neoplasia incidence were described on 4 campaigns (≤2008, 2009-2010, 2011-2012 and 2013-2014) with a Guaiac FOBT (gFOBT) and a first campaign (2015-2016) with a Fecal Immunochemical Test (FIT). The cumulative incidence was estimated by the actuarial method and its confidence interval by the Greenwood method.

Results: The participation rate decreased from 32.7% (first gFOBT-campaign) to 24.4% (fourth gFOBT-campaign) then, made a significant bound in the FIT-campaign (28.4%; p < 0.001). 35.4% of the 965 high-risk-polyps screened in this cohort were detected in the FIT-campaign. CRC incidence gradually decreased from 0.4 to 0.1/1000 person-years from the first to the fourth gFOBT-campaign before reaching a bound to 0.4/1000 person-years in the FIT-campaign.

Conclusion: Although it was still below the minimum European target (45%), the participation rate has increased between the last gFOBT-campaign and FIT-campaign, justifying the impact of promotional campaigns and the acceptance of the new test by people and GPs. A decline in the neoplasia incidence was observed between the initial and the fourth gFOBT-campaign. The change from gFOBT to FIT between the fourth and fifth campaigns, was associated with a significant increase in detection of neoplasia.