We will use the well-established MIcrosimulation SCreening ANalysis for CRC (MISCAN-Colon) model [19, 20] to estimate harms, benefits, resources and costs of uniform screening with a biennial interval and compare that with those of personalized screening intervals of 1, 2 or 3 years based on prior f-Hb concentrations. This evidence concerns the gene GSTM1 and colorectal carcinoma.