The Impact Of Colorectal Neoplasm Resection On Gut Microbiota

Objective: The study investigated the impact of colorectal cancer radical surgery and colorectal adenoma endoscopic resection on gut microbiota,aiming to pave the way for noninvasive microbial marker for prognosis prediction and recurrence mornitoring of colorectal cancer as well as prediction of adenoma recurrence.Methods: The fecal samples were collected from 412 preoperative patients with colorectal cancer,119 postoperative patients and 270 healthy controls at two centers,and preoperative and early postoperative(within 3 months)samples were collected from 33 patients with colorectal cancer at Renji Hospital.The fecal abundance of Fusobacterium nucleatum(F.nucleatum)was measured by quantitative polymerase chain reaction,and the postoperative alterations were tested and validated in the two cohorts respectively.At the same time,preoperative and postoperative samples from 20 patients with colorectal adenoma who underwent endoscopic resection at Renji Hospital were collected,and Miseq sequencing of 16 S rRNA gene V3-V4 region was used to analyze the alterations in microbial diversity and structure.Furthermore,random forest and receiver operating characteristic analysis were applied to select a genus model with a discriminating performance between two groups.Results: The enrichment of fecal F.nucleatum in patients with cancer showed a rapid decline after surgery,which happened in the early postoperative period(P<0.001).Desipte no significant changes in overall microbial structure after adenoma resection,the abundance of protective Parabacteroides revealed a drastic increase postoperatively(2.70% vs 1.43%,P=0.0263),and the united model based on Parabacteroides,Streptococcus and unclassified genus in Lachnospiraceae showed an optimal discriminating performance of postoperative status in receiver operating characteristic analysis(area under the curve 0.768,P <0.001).Conclusions: The rapid decline of fecal F.nucleatum abundance after radical surgery paves the way for its application as a noninvasive marker for prognosis prediction and recurrence mornitoring of colorectal cancer.And the microbial improvement after adenoma resection lays the groundwork for the application of the united model for prediction of adenoma recurrence.Besides,the impact of colorectal neoplasm resection on the intestinal flora is of great importance on the causality between them.