The Impact of the Gut Microbiome, Environment, and Diet in Early-Onset Colorectal Cancer Development

Abstract

Traditionally considered a disease common in the older population, colorectal cancer is increasing in incidence among younger demographics. Evidence suggests that populational- and generational-level shifts in the composition of the human gut microbiome may be tied to the recent trends in gastrointestinal carcinogenesis. This review provides an overview of current research and putative mechanisms behind the rising incidence of colorectal cancer in the younger population, with insight into future interventions that may prevent or reverse the rate of early-onset colorectal carcinoma.

Keywords: EOCRC; adenocarcinoma; birth-cohort effect; clinical translation; diet; early-onset colorectal cancer; environmental exposures; gut microbiome; inflammation; risk factors; young onset.

Figure 1

Change in incidence of colorectal carcinoma since 1999. Since 1999, there has been a steady decline in the incidence of colorectal carcinoma on a population basis (A). However, in patients younger than 49 years old, there has been a disproportionate increase in relative risk compared to the rest of the population (B). Data Source: https://www.cdc.gov/cancer/uscs/dataviz/download_data.htm (accessed on 6 December 2023) [10].

Figure 2

Summary of mechanisms that microbiome dysregulation may contribute to colorectal carcinogenesis and the increase in early-onset colorectal carcinoma.