Abstract
Young-onset colorectal cancer (YOCRC) is increasingly common in the Western world. This has been attributed to changes in diet, lifestyle, and other environmental factors which all influence the gut microbiome. This review summarizes a small number of studies that have demonstrated differences in the microbiome of YOCRC, assessed in the stool and tumoral compartment. These populations are distinct from LOCRC and are prognostically important. Further research may reveal their role in the pathogenesis of this epidemic, and microbiological interventions can alter or augment existing treatment responses.