Lennart Friis-Hansen, Department of Clinical Biochemistry, Hilleroed Hospital, Hilleroed, Denmark; Member of Danish Colorectal Cancer Screening Database (DCCSD) steering committee., Danmark
Niels Daniel Hansen de Haas, Aalborg Universitet
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Dorte Linnemann, Department of Pathology, Herlev and Gentofte Hospital, Herlev, Denmark; Member of Danish Colorectal Cancer Screening Database (DCCSD) steering committee, Denmark.
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Henrik Nørgaard, Department of Radiology, Herlev Hospital, University of Copenhagen, Herlev, Denmark., Danish Colorectal Cancer Screening Database (DCCSD) steering committee, Danmark
Ole Roikjær, Department of Surgery, Zealand University Hospital, Roskilde, Denmark; Member of Danish Colorectal Cancer Screening Database (DCCSD) steering committee, Denmark.
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Bo Søndergaard, Gastrounit, Medical Division, Hvidovre University Hospital, Hvidovre, Denmark; Member of Danish Colorectal Cancer Screening Database (DCCSD) steering committee, Denmark.
Background: Colorectal cancer (CRC) screening programs using fecal immunochemical test (FIT) have to choose a cut-off value to decide which citizens to recall for colonoscopy. The evidence on the optimal cut-off value is sparse and based on studies with a low number of cancer cases.
Methods: This observational study used data from the Danish Colorectal Cancer Screening Database. Sensitivity and specificity were estimated for various cut-off values based on a large number of cancers. Traditionally optimal cut-off values are found by weighting sensitivity and specificity equally. As this might result in too many unnecessary colonoscopies we also provide optimal cut-off values for different weighting of sensitivity and specificity/number of needed colonoscopies to detect one cancer.
Results: Weighting sensitivity and specificity equally gives an optimal cut-off value of 45 ng Hb/ml. This, however, means making 24 colonoscopies to detect one cancer. Weighting sensitivity lower and for example, aiming at making about 16 colonoscopies to detect one cancer, gives an optimal cut-off value of 125 ng Hb/ml.
Conclusions: The optimal cut-off value in an FIT population-based screening program is 45 ng Hb/ml, when as traditionally sensitivity and specificity are weighted equally. If, however, 24 colonoscopies needed to detect one cancer is too huge a burden on the health care system and the participants, 80, 125, 175, and 350 ng Hb/ml are optimal cut-off values when only 19/16/14/10 colonoscopies are accepted to find one cancer.