Narrative Review of the Use of Genomic-Adjusted Radiation Dose (GARD) in Radiotherapy.

This narrative review examines the genomic-adjusted radiation dose (GARD), a biologically informed framework developed to personalize radiotherapy by integrating tumor-specific genomic data. GARD combines the radiosensitivity index (RSI), based on gene expression, with the linear quadratic model to estimate patient-specific radiation effect. Since its introduction in 2017, GARD has demonstrated prognostic value across multiple cancer types in retrospective studies. This review summarizes key studies evaluating GARD across various tumor types and clinical contexts. Emerging trials, including a Phase II trial in HPV-positive oropharyngeal cancer, aim to validate GARD-guided dosing in precision radiotherapy. Future efforts may focus on refining RSI, addressing tumor heterogeneity, and validating GARD-guided dosing in prospective settings.