Abstract 4920: Evaluation of a diagnostic blood test for colorectal cancer screening and as a triage tool to stratify patients for colonoscopy
Authors: Cosgrove Leah J. , Surinya Kathy , Fung Kim YC , Priebe Ilka , Buckley Mike , Adams Tim , Tabor Bruce , Purins Leanne , Lockett Trevor , Leroux Hugo , Gibbs Peter , Wei Jiangqin , Nice Ed , Burgess Tony , Thomas Michelle , Moore James , Singh Raj , Ruszkiewicz Andrew 
Published: July 2016

Abstract
Worldwide, colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer death, with an annual incidence in 2012 of 1.4 million CRC cases and an annual mortality around 700,000 [1]. Fortunately the majority of colorectal cancer (CRC) cases are preventable by early detection and removal by colonoscopy or surgery. Currently in Australia, the only widely used non-invasive screening test for CRC is the immunological faecal occult blood test (iFOBT), which has been shown to reduce CRC incidence and mortality by 15-25% [2]. There are however significant issues that limit its effectiveness as a diagnostic screening tool, such as a poor positive predictive value of 5.3% for suspected cancer and low participation rate of approximately 33.5% in 2013, as seen in the Australian National Bowel Cancer Screening Program (NBCSP)[2]. Evidence indicates a robust, blood-based, diagnostic assay would increase screening participation and compliance. In our systematic analysis of 68 individual biomarkers using logistic regression strategies, we have identified a unique 3 protein biomarker panel blood test consisting of Insulin like growth factor binding protein 2 (IGFBP2), Dickkopf-3 (DKK3), and Pyruvate kinase M2(PKM2)[3]. This panel not only differentiates between CRC and normal patient sera with 95% specificity and 73% sensitivity in a single measurement (c.f. FOBT: 35-50 sensitivity [4]) but early stage disease. Currently, we are prospectively collecting a new cohort of over 1,000 blood samples from volunteers that have undergone colonoscopy, that include CRC patients, controls and other pathologies (IBD, other cancers) to specifically determine the performance of this blood test in asymptomatic and surveillance screening populations. We will also evaluate directly the accuracy and performance of our biomarker panel, as a diagnostic test suitable for CRC screening versus the iFOBT used in the NBCSP, as an intermediary test in the triage of individuals with positive iFOBT result for need and urgency to have a colonoscopy.
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2. National Bowel Cancer Screening Program: monitoring report 2012-2013. AIHW & Australian Government Department of Health and Ageing, 2014.
3. Fung KYC et al 2015. Blood-based protein biomarker panel for the detection of colorectal cancer. PloS one. 2015;10(3):e0120425.
4. Morikawa, T et al., A comparison of the immunochemical fecal occult blood test and total colonoscopy in the asymptomatic population. Gastroenterology, 2005. 129(2): p. 422-8.
Citation Format: Leah J. Cosgrove, Kathy Surinya, Kim YC Fung, Ilka Priebe, Mike Buckley, Tim Adams, Bruce Tabor, Leanne Purins, Trevor Lockett, Hugo Leroux, Peter Gibbs, Jiangqin Wei, Ed Nice, Tony Burgess, Michelle Thomas, James Moore, Raj Singh, Andrew Ruszkiewicz. Evaluation of a diagnostic blood test for colorectal cancer screening and as a triage tool to stratify patients for colonoscopy. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4920.