Gut microbiota shifts in patients with gastric cancer in perioperative periodOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study characterized how the fecal gut microbiota shifts in gastric cancer (GC) patients across the perioperative period. It compared patients before and after radical distal gastrectomy (RDG). It also compared GC patients with healthy controls. Bacterial load in feces was measured by quantitative PCR. The 16S rRNA gene was pyrosequenced to profile diversity and composition. Short-chain fatty acids were measured by gas chromatography in the surgical subset.
Who was studied?
The cohort was 20 patients with advanced distal gastric adenocarcinoma and 22 healthy controls, all of Chinese origin. The patients averaged about 52 years old, and controls about 53. The 20 tumors comprised 13 intestinal-type and 7 diffuse-type cancers. Six of the GC patients provided paired fecal samples before and after RDG. No participant had taken antibiotics, acid suppressants, or probiotics in the month before sampling. In total, 48 fecal samples were analyzed.
What were the most important findings?
Compared with healthy controls, GC patients had higher abundances of Escherichia/Shigella, Veillonella, and Clostridium XVIII, and lower Bacteroides. GC patients showed increased richness (Chao1 p=0.0002; ACE p=0.002) but a decreased Shannon diversity index (p=0.04). RDG had a moderate effect on richness but a pronounced effect on composition. The genera Akkermansia, Escherichia/Shigella, Lactobacillus, and Dialister changed significantly after surgery. Fecal valerate fell significantly after RDG (p less than 0.05), with non-significant downward trends in acetate, propionate, and butyrate.
What are the greatest implications of this study?
The work shows noninvasive stool sampling can track gut microbiota changes in gastric cancer patients through surgery. Post-surgical loss of beneficial short-chain fatty acids like valerate may weaken the intestinal barrier and warrants attention. The main limitation is the small sample size, especially the six paired surgical cases and one postoperative timepoint. The study is observational and cannot establish causation between the microbial shifts and clinical outcomes.