Colonosight: Multitarget RNA-FIT assay for noninvasive detection of advanced colorectal neoplasia.

Abstract

25 Background: Effective colorectal cancer (CRC) prevention and screening requires sensitive detection of all advanced neoplasias (colorectal cancer and advanced adenomas). Existing noninvasive screening approaches cannot accurately detect precancerous adenomas with high sensitivity. Here we describe a multi-factor assay (RNA-FIT test) that combines 8 stool-derived eukaryotic RNA (seRNA) biomarkers, patient demographic information (smoking status), and a fecal immunochemical test (FIT) to sensitively detect advanced colorectal neoplasias and other precancerous adenomas in a 1,305 average risk (45-75 age) prospective cohort. Methods: Average-risk patients undergoing colorectal cancer screening were prospectively evaluated with the RNA-FIT assay prior to an optical colonoscopy. RNA-FIT test results were generated using an ordinal regression model and results were compared to the colonoscopy findings. The model was initially assessed via 5-fold internal cross-validation of the training set and the ultimate model performance was assessed on a hold out testing set. Results: Of the 1,305 eligible patients recruited, 939 were included in the training set and 366 samples were reserved for the hold out testing set. When evaluating all 5 folds of the training set, internal cross validation attained a 61% sensitivity for advanced neoplasias (n = 69), 22% sensitivity for other adenomas (n = 279), 80% specificity for hyperplastic polyps (n = 155) and 86% specificity for no findings on a colonoscopy (n = 436). When employed on the testing set, the RNA-FIT test attained a 62% sensitivity for advanced neoplasias (n = 52), 27% sensitivity for other adenomas (n = 139), 78% specificity for hyperplastic polyps (n = 74) and 84% specificity for no findings on a colonoscopy (n = 101). Sensitivity for colorectal cancer and advanced adenomas with high-grade dysplasia / carcinoma in-situ was 100% in both the training set (n = 6) and hold out testing set (n = 5). Sensitivity for villous / tubulovillous adenomas was 65% in the training set (n = 23) and 60% in the hold out testing set (n = 15). Additional retrospective sample collection from patients with CRC is ongoing to further validate assay sensitivity for CRC. Conclusions: The RNA-FIT assay demonstrated clinically relevant detection of all advanced neoplasia, including early carcinomas, advanced adenomas, and other precancerous lesions. This assay could represent a noninvasive option to prevent colorectal cancer development through precancerous adenoma detection.