Assessment of leukemia risk associated with ionizing radiation exposure

Ionizing radiation is a recognized leukemogenic agent capable of inducing DNA damage in hematopoietic stem and progenitor cells. This narrative review aims to summarize epidemiological and biological evidence regarding leukemia risk associated with ionizing radiation exposure from medical, occupational, and environmental sources. The review focuses on dose–response relationships, biological mechanisms, susceptible populations, and radiation protection strategies, while highlighting current uncertainties related to low-dose radiation exposure. A structured narrative literature review was conducted using PubMed, Scopus, and Web of Science databases covering publications from 1990 to 2025. Evidence from atomic bomb survivor cohorts, medical radiation studies, occupational cohorts, and environmental exposures was analyzed to evaluate dose–response relationships and biological mechanisms. Strong evidence demonstrates increased risks of acute myeloid leukemia (AML) and chronic myeloid leukemia (CML) following moderate-to-high radiation doses, particularly among atomic bomb survivors and radiotherapy patients. Epidemiological evidence also suggests elevated leukemia risk following cumulative bone marrow doses of approximately 30–50 mGy from repeated CT imaging during childhood. Occupational studies such as the INWORKS cohort demonstrate a positive linear association between cumulative radiation dose and leukemia mortality excluding chronic lymphocytic leukemia. Mechanistically, ionizing radiation induces double-strand DNA breaks, chromosomal aberrations, genomic instability, and alterations in the bone marrow microenvironment that promote leukemogenesis. Although high-dose effects are well established, uncertainties remain regarding leukemia risk from low-dose exposures. Continued research integrating epidemiological, molecular, and genomic approaches is essential to improve risk assessment models and optimize radiation protection practices.