Abstract A004: Molecular adenoma features to predict metachronous colorectal cancer risk: A nested-case control study

Abstract Introduction: In colorectal cancer (CRC) surveillance, adenoma characteristics such as size, number of adenomas, dysplasia, and villous components, are used as indicators for risk of developing metachronous cancer and guide the surveillance interval. The current risk groups (e.g., advanced adenomas) cannot optimally distinguish high risk from low risk, which may result in suboptimal surveillance strategies. Specific DNA copy number aberrations are associated with risk of colorectal adenoma-to-carcinoma progression, but these aberrations are present in only a subset of advanced adenomas. Therefore, we hypothesize that specific DNA copy number aberrations may better predict the risk of CRC than advanced adenoma. Aim: To evaluate whether a molecularly-defined high-risk adenoma is a better risk factor for CRC than the presently used advanced adenoma. Materials and methods: DNA copy number profiles were determined, by means of low-coverage whole genome sequencing, on a series of 529 adenomas, selected from a Norwegian adenoma cohort. We retrieved detailed information on adenoma characteristics and whether adenoma patients were subsequently diagnosed with CRC or not. By univariate and multivariate regression analysis we estimated the odds ratio for association between the development of CRC and baseline presence of advanced adenoma versus presence of a molecularly-defined high-risk adenoma, respectively. Results: Molecular high-risk features were observed in 85/267 (32%) of advanced adenomas and in 27/262 (10%) of non-advanced adenomas. The odds ratio for developing metachronous CRC was 3.58 (p=2.84E-8) and 1.90 (p=0.012), when an advanced adenoma or molecular high-risk adenoma was detected at the baseline colonoscopy, respectively. In the multivariate regression analysis only advanced adenoma was as a significant risk factor for CRC. Conclusion: Molecularly-defined high-risk adenomas are associated with an increased risk of CRC. However, the advanced adenoma is a stronger predictor for risk of CRC. Citation Format: Henriette C. Jodal, Eddymurphy U. Akwiwu, Leticia G. Leon, Margriet Lemmens, Pien Delis-van Diemen, Dagmar Klotz, Meike de Wit, Remond Fijneman, Monique van Leerdam, Evelien Dekker, Manon C. W. Spaander, Gerrit A. Meijer, Michael Bretthauer, Magnus Løberg, Veerle M. H. Coupé, Mette Kalager, Beatriz Carvalho. Molecular adenoma features to predict metachronous colorectal cancer risk: A nested-case control study [abstract]. In: Proceedings of the AACR Special Conference on Colorectal Cancer; 2022 Oct 1-4; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;82(23 Suppl_1):Abstract nr A004.