Abstract 4519: A non-invasive test for right-sided colonic neoplasia in diabetics at increased risk, independent of drug therapy and demographics
Authors: Tobi Martin , Yang Yu-Xiao , Kaplan David , Gupta Rasna , Rambus MaryAnn , Naumoff Joanne , Leavell Bonita , Patel Pragnesh , Sochacki Paula , Hatfield James , Lawson James 
Published: August 2012

Evidence accrues that screening colonoscopy in average-risk patients does not reduce mortality from right-sided neoplasia. A non-invasive test that differentially identifies right-sided neoplasia is urgently needed to direct investigative colonoscopy. The metabolic syndrome is associated with excess colorectal neoplasia but many medications that treat the diabetic component of this syndrome may alter carcinogenesis pathways (PPARδ in de novo for thiazolidinediones etc) and may thus confound our ability to design such a test. Methods: We investigated 122 patients, 45 diabetics and 77 non-diabetics at above average risk identified by screening by a risk questionnaire, for colorectal cancer. The patients were enrolled to participate in a prospective colorectal cancer screening study at the Detroit VAMC and intake of metformin, thiazolidinediones, ASA, NSAID, sulfonylureas, statins, insulin, and multivitamins was determined. We ascertained demographics, nutritional parameters (total caloric, protein and vitamin intake, BMI, alcohol intake, fried food, etc). Primary outcomes were colorectal neoplasia (adenomas & cancers) found on colonoscopy. Secondary endpoints were: adenoma-carcinoma biomarker binding in body fluids and mucosal field effects using the Adnab-9 monoclonal antibody. These diagnostic tests were also examined in the cohort of 77 of non-diabetics to ascertain whethera specific test was also applicable to the non-diabetic population at increased risk for CRC. Results: Of 45 diabetic patients with evaluable data, 26.6% had right-sided neoplasia. Of these 50% had positive binding compared to 13.8% without such neoplasia. There was a significant correlation between Adnab-9 effluent binding and right-sided neoplastic lesions (OR 6.45;CI 1.48-26.39;p&lt;0.001). Adnab-9 effluent binding showed a 67% sensitivity and 76% specificity for right sided lesions, True positive=50% and True Negative=86% with a likelihood ratio of 2.75 (CI 1.33-5.67) for a positive test and 0.44 (0.19-0.998) for a negative test. There was no significant differential binding in the non-diabetic population (OR1.74;CI 0.59-5.11). There were also no statistically significant differences between the above medication groups or with other characteristics that included age, diabetes duration, BMI, HbA1c, GFR, and nutritional parameters with respect to neoplasia prevalence. Other adenoma-carcinoma biomarker binding in stool or mucosa was not significantly different between those with or without neoplasia. Conclusions: Adnab-9 Effluent binding may differentially identify most diabetics with right-sided colonic neoplasia independent of medication and other parameters. Prospective studies will be needed to determine the impact of this test in the reduction of mortality from right-sided CRC in this high-risk group.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4519. doi:1538-7445.AM2012-4519