Two-sample FIT-screening: a 4th screening round

Colorectal cancer (CRC) is one of the major causes of death in the Netherlands, accounting for over 5100 deaths in 2010. Population screening aims to detect CRC in an earlier phase, thereby reducing CRC morbidity and mortality. Long-term randomized prospective trials using guaiac-based fecal occult blood testing (gFOBT) have proven to decrease CRC related mortality. Currently the classical gFOBT is being replaced by the fecal immunochemical test (FIT), as FIT is more specific to lower-digestive tract blood loss and leads to higher participation and detection rate. While gFOBT samples on multiple consecutive bowel movements, standard FIT only uses one sample from one bowel movement. Since advanced neoplasia can bleed intermittently, it may be missed with single stool sampling. Screening by means of a 2-sample FIT can reduce the risk of missing advanced lesions, and therefore increase test sensitivity. People aged 50-75 years will receive two identical FITs (OC-sensor, Eiken Japan) to sample from two consecutive bowel movements.

The cut-off level for positivity will be 10 µg hemoglobin per gram feces, which is the lowest level used worldwide, enabling comparison and modeling for different cut-off levels. Participants with at least one positive test will be offered colonoscopy.

We aim to determine participaton and diagnostic yield of repeated 2-sample FIT screening. We will also compare these data with repeated 1-sample FIT screening to assess the additional yield of 2-sample FIT screening to current screening strategies. We will focus on cumulative yield after four rounds, as well as comparing yield per round. These data will give us insight in alternative screening strategies and provides the opportunity to optimize implementation of the nation-wide colorectal cancer screening program.

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People will receive two identical FITs (OC-sensor, Eiken Japan) to sample from two consecutive bowel movements.