Novel fecal microbial biomarkers for noninvasive diagnosis of colorectal cancer and advanced adenomas: A prospective multicenter cohort study

To the Editor: Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide and the second leading cause of cancer-related mortality, underscoring the critical need for effective non invasive screening.[1] Current tools like the fecal immunochemical test (FIT) are suboptimal for detecting precancerous advanced adenomas (AAs).[2] Alterations in the gut microbiome are strongly implicated in colorectal tumorigenesis, offering a promising avenue for novel biomarkers.[3] The prospective multi center study aimed to evaluate the diagnostic performance of a panel of four fecal microbial biomarkers: Fusobacterium spp. (Fn), Hungatella hathewayi (Hh), Lachnoclostridium sp. (m3), and Christensenella hongkongensis (Chk) combined with FIT for the non invasive detection of CRC and AA. This prospective, multi center diagnostic study was approved by the Ethics Committee of Beijing Friendship Hospital, Capital Medical University (No. 2022-P2-084). We consecutively recruited adults scheduled for colonoscopy from five centers located across northern, southern, eastern, and western China, including Beijing Friendship Hospital affiliated with Capital Medical University, the First Affiliated Hospital of Kunming Medical University, Renji Hospital affiliated with Shanghai Jiaotong University School of Medicine, Xijing Hospital, and the Sixth Affiliated Hospital of Sun Yat-sen University, from July 2022 to December 2023. Exclusion criteria included a history of inflammatory bowel disease or antibiotic use within 30 days before stool collection. Informed consent was obtained from all participants. Control status was defined as participants with normal colonoscopy findings, or with findings limited to non-AAs or non-adenomatous polyps, as confirmed by the gold-standard method of colonoscopy and histopathological examination. Stool samples were collected within 30 days before bowel preparation and immediately stored at −80°C. Genomic DNA was extracted from each sample using the Baypure Magnetic Stool Nucleic Acid Kit (Baybio Biotek Corp, Guangzhou, China). The detection reagent “M3CRC” (MicroSigx Biotech Diagnostic, Guangzhou, China) was used for simultaneous quantification of microbial gene markers and FIT analysis according to the manufacturer’s protocol. Quantitative polymerase chain reaction (qPCR) was performed for microbial quantification, and FIT was conducted on the DFIA300 fluorescence immunoanalyzer (Guangzhou Biotron Technology Co., Ltd., Guangzhou, China), with technicians blinded to the clinical diagnoses. The primary outcome was the ability of fecal microbial biomarkers combined with FIT to detect CRC and AA (adenomas with a diameter of ≥1 cm, with a tubulovillous or villous component, or with high-grade dysplasia). The secondary outcome was the performance of this combined model in identifying early-stage CRC (AJCC [American Joint Committee on Cancer] Stages I-II) and high-risk AA (defined by high-grade dysplasia). A prototypical STARD (Standards for Reporting of Diagnostic Accuracy Studies) diagram [Supplementary Figure 1, https://links.lww.com/CM9/C784], detailed laboratory protocols, and statistical analysis methods are provided in the Supplementary Materials, https://links.lww.com/CM9/C784. A total of 821 participants were enrolled, comprising 285 patients with CRC, 70 with AA, and 466 controls. Baseline characteristics are summarized in Supplementary Table 1, https://links.lww.com/CM9/C784. The relative abundances of the fecal microbial biomarkers Fn, m3, Hh, and Chk differed significantly among these groups. All four biomarkers were significantly elevated in the CRC group compared to controls (P