Published in:
Clinical and Translational Gastroenterology (2022)
Language:
English
DOI:
10.14309/ctg.0000000000000458
ISSN:
2155-384X
Origination:
Footnote:
Description:
Introduction: Prevalence of colorectal neoplasms varies by polygenic risk scores (PRS). We aimed to assess to what extent PRS might be relevant for defining personalized cutoff values for fecal immunochemical tests (FITs) in colorectal cancer (CRC) screening. Methods: Among 5,306 participants of screening colonoscopy who provided a stool sample for a quantitative FIT (Ridascreen Hemoglobin or FOB Gold) prior to colonoscopy a PRS was determined, based on the number of risk alleles in 140 , single nucleotide polymorphism. Subjects were classified into low, medium and high genetic risk for colorectal neoplasms according to PRS tertiles. We calculated positive predictive values (PPVs) and numbers needed to scope (NNS) to detect one advanced neoplasm (AN) by risk group, and cutoff variation needed to achieve comparable PPVs across risk groups in the samples tested with Ridascreen (N=1,271) and FOB Gold (N=4,035) independently, using cutoffs yielding 85%, 90% or 95% specificity. Results: Performance of both FITs was very similar within each PRS group. For a given cutoff, PPVs were consistently higher by 11%-15% units in the high-risk PRS group compared to the low-risk group (all P-values <0.05). Correspondingly, numbers needed to scope (NNS) to detect one advanced neoplasm varied from 2 (high PRS, high cutoff) to 5 (low PRS, low cutoff). Conversely, very different FIT cutoffs would be needed to ensure comparable PPVs across PRS groups. Discussion: PPVs and NNS of FITs varied widely across people with high and low genetic risk score. Further research should evaluate the relevance of these differences for personalized CRC screening. Funding Source: This study was partly funded by grants from the German Research Council (DFG, grant No. BR1704/16-1), the Federal Ministry of Education and Research (BMBF, grant no. 01GL1712), and the German Cancer Aid (No. 70113330).