Evidence-based selection on the appropriate fit cut-off point in crc screening programs in the covid pandemic

Introduction: The COVID pandemic has forced the closure of many colorectal cancer (CRC) screening programs around the world. Resuming these programs is a priority, but fewer colonoscopies may be available. Aims & Methods: The aim of the study is to develop an evidence-based tool for decision-making in CRC screening programs, based on a fecal hemoglobin immunological test (FIT), to optimize the strategy for screening a population for CRC. We retrospectively analyzed data collected at a regional CRC screening program between February/2014 and November/ 2018. We investigated two different scenarios: not modifying (scenario 1) vs. modifying the FIT cut-off value (scenario 2). We estimated program outcomes in the two scenarios by evaluating the numbers of cancers and adenomas missed or not diagnosed in due time (delayed). Results: The current FIT cut-off (20-mg hemoglobin/g feces) led to 6606 colonoscopies per 100,000 people invited annually. Without modifying this FIT cut-off value (scenario 1), when the number of colonoscopies available was reduced by 10-30%, a high non-negligible number of CRCs and adenomas (low, intermediate, and high risk) were undetected. As shown in the Table 1, when the FIT cut-off value was increased to where the colonoscopy demand matched the colonoscopy availability (scenario 2), the number of missed lesions was remarkably reduced. Moreover, the unmodified FIT scenario outcomes were improved by prioritizing the selection process based on sex (prioritized call criterion), rather than randomly reducing the number invited (random call criterion). Conclusion: Assuming a mismatch between the availability and demand for annual colonoscopies, increasing the FIT cut-off point was more effective than randomly reducing the number of people invited. Using specific risk factors (sex and age, for example) to prioritize access to colonoscopies should be also considered.