A Multicenter Clinical Trial of Stool-based DNA Testing for Early Detection of Colon Cancer in China

Overview

According to data from Global Cancer Statistics 2018, colorectal cancer (CRC) ranks second in incidence and fifth in mortality among all cancers in China. The underlying neoplastic progression from adenoma to CRC endures up to 10 years, providing an extended window for CRC detection and screening. Currently, fecal occult blood test (FOBT) and colonoscopy are the main diagnostic and screening methods for CRC in Chinese clinical practice. However, due to low patients' compliance with colonoscopy and poor sensitivity of FOBT, a large proportion of CRC could not be effectively diagnosed and treated at early stage. Therefore, noninvasive fecal DNA detection approach with enhanced performance is urgently needed in clinic. The aim of this trial is to evaluate effectiveness of the Human Multigene Methylation Detection Kit (Fluorescent PCR) for auxiliary diagnosis of colorectal cancer. By assessing the level of DNA methylation of certain genes in human stool, the test can indicate whether cancerous and precancerous lesions exist in the areas of colon and rectum.

The multicenter clinical trial will be conducted using a single-blind method. Stool samples provided by participants will be evaluated by Human Multigene Methylation Detection Kit (Fluorescent PCR). The kit will be used to qualitatively detect methylation levels of multiple genes in human stool samples in vitro by using Quantitative Methylation Specific PCR (qMSP). The principle of the method is as follows. First, the target DNA in human stool is extracted by magnetic bead-capture technology and then treated with sodium bisulfite. The sequence of unmethylated DNA will be changed while that of the methylated DNA remains the same after sodium bisulfite treatment. Subsequently, qMSP is employed to detect methylation levels of target genes in addition to ACTB gene (a reference gene). Controls of ACTB gene with and without methylation are tested simultaneously. Result of qMSP is dichotomized as positive and negative based on Ct value obtained. The test result is then verified by Sanger sequencing and compared with that from colonoscopy examination and pathology report. The main evaluation indexes for test performance are sensitivity, specificity, consistency rate, kappa coefficient.