Effects of low and moderate doses of ionizing radiation on colon carcinogenesis: Experimental models and current evidence.

Millions of people are exposed annually to low and moderate doses of ionizing radiation (LMDR), mostly as a result of medical diagnostic procedures. These individuals may be at increased risk of developing colon cancer (CC), as predicted by the linear no-threshold model used for radioprotection. However, risk estimates derived from epidemiological studies remain subject to considerable uncertainty, necessitating a better mechanistic understanding of how LMDR may contribute to CC development. This review examines available experimental models for CC research and current evidence describing the effects of LMDR on colonic (and relevant intestinal) tumor development, including effects on cell proliferation, stemness, epigenetic modifications and oxidative stress, and their relevance for CC risk estimation. The review highlights the complex roles LMDR may play in colon carcinogenesis, underscores knowledge gaps and suggests priorities for future studies, with the overarching goal of improving our understanding of LMDR effects on colon cancer.