IDDF2022-ABS-0108 Clinical validation of a faecal bacterial signature test for colorectal cancer screening. (2nd September 2022)

• Record Type: Journal Article
• Authors: Malagón, Marta; Oliver, Lia; Ramió-Pujol, Sara; Sánchez-Vizcaino, Mireia; Amoedo, Joan; Serra-Pagès, Mariona; Castells, Antoni; Aldeguer, Xavier; Garcia-Gil, Jesús
• Is Part Of: Gut. Volume 71(2022)Supplement 2
• Page Start: A48
• Page End: A48
• Publication Date: 2022-09-02
• Subjects: Gastroenterology -- Periodicals; 616.33
• DOI: 10.1136/gutjnl-2022-IDDF.52
• Languages: English
• ISSNs: 0017-5749

Abstract

Abstract : Background: The faecal immunochemical test (FIT) is the most widely used test for colorectal cancer (CRC) screening. RAIDCRCScreen is a non-invasive test based on faecal biomarkers that complement FIT by increasing its specificity. It was previously clinically evaluated in FIT-positive patients (>20µg haemoglobin/g faeces, 'FIT20'), in which it reduced the proportion of false-positive (FP) results by 16.3% for CRC and for advanced neoplasia (AN) while maintaining FIT20's sensitivity for CRC detection. The aim was to demonstrate superiority in specificity and non-inferiority in sensitivity of the RAIDCRCScreen versus FIT20 in a screening cohort undergoing colonoscopy. Methods: A cohort of 2481 subjects aged >55 years from the German CRC screening program was retrospectively included in the DKFZ. They collected a faecal sample prior to colonoscopy to analyse the FIT and the RAID-CRC-Screen test. Results: RAIDCRCScreen maintained the sensitivity of FIT20 (66.7%) for CRC detection while showing a significantly higher specificity (97.0% vs. 96.1%, p<0.0001). The positive predictive value was higher for RAIDCRCScreen (11.9%) compared with FIT20 alone (9.5%), and the negative predictive value was 99.8% for the two tests. The sensitivity of RAIDCRCScreen in detecting AN was significantly lower compared with FIT20 alone (19.9% vs. 24.8%, p<0.001), whereas the specificity was significantly higher (98.3%) compared with FIT20 alone (97.8%) (p<0.005). In terms of added value over FIT, RAIDCRCScreen reduced the proportion of FIT20 FP by 22.1% while maintaining 100% the proportion of true positives identified by FIT20. For the detection of AN, RAIDCRCScreen decreased the FP rate by 20.4%. The proportion of FIT20 true positives that RAIDCRCScreen still identified was reduced to 80.4%. These results are in line with those obtained in previous studies for both CRC and AN endpoint. Conclusions: Our results elucidate the potential of RAIDCRCScreen to improve the precision of the current CRC screening avoiding unnecessary colonoscopies. The introduction in clinical practice of a three-step CRC screening strategy in which RAIDCRCScreen is performed in FIT-positive individuals can help to rationalize the allocation of resources and alleviate the assistential and economic burden of the healthcare system.