Vitamins as radiosensitizers exploring mechanisms and preliminary cancer treatment prospects

Radiotherapy remains a fundamental modality in cancer treatment; however, its clinical efficacy is frequently constrained by heterogeneous tumor radiosensitivity and treatment-associated toxicities. Although the supporting evidence remains largely preliminary, vitamins—as readily accessible micronutrients—have been hypothesized to function as potential radiosensitizers. To address this gap, this review systematically examines the proposed mechanisms through which vitamins may modulate radiotherapy responses, including the modulation of oxidative stress, DNA damage repair, cell cycle regulation, and remodeling of the tumor immune microenvironment. Furthermore, this review integrates existing preclinical data and currently sparse, early-phase clinical evidence, explores key translational challenges including dose optimization and inter-individual variability, and outlines future interdisciplinary research directions, so as to inform the rational design and rigorous evaluation of vitamin-based radiosensitization strategies in precision oncology.