Mapping the Research Landscape of the Correlation Between Radiotherapy and Tumor Immune Microenvironment: A Bibliometric Analysis

Abstract Background Radiation therapy (RT) is a cornerstone of cancer treatment that not only directly kills tumor cells but also produces synergistic effects with immunotherapy by remodeling the tumor immune microenvironment (TIME). However, systematic bibliometric analyses of RT‐TIME interactions remain unexplored. Methods This study analyzed all the literature related to RT and TIME from the Web of Science (WOS) Core Collection through 2024. It utilized R, VOSviewer, and CiteSpace to visually analyze authors, countries, institutions, keywords, co‐cited references, research hotspots, and frontiers. Results China, the United States, and Germany emerged as the leading contributors, with 1,253, 581, and 162 publications, respectively. Frontiers in Immunology was the most active journal (n = 186). Co‐occurrence analysis identified “radiotherapy” (n = 898) and “immunotherapy” (n = 895) as core themes, with sustained focus on “CD8(+) T cells” (citation burst = 8.81) and emerging interest in “(nature killer) NK cells.” Temporal evolution revealed three research phases: initial exploration (2007–2015) of RT's immunomodulatory mechanisms of RT, clinical validation of RT combined with Programmed Cell Death Protein 1 (PD‐1)/ Cytotoxic T‐Lymphocyte‐Associated Protein 4 (CTLA‐4) inhibitors (2015–2020), and recent diversification (2020–2024) toward technical optimization (e.g., stereotactic RT), tumor type expansion, and safety management. Conclusions This comprehensive bibliometric analysis highlights future priorities, including exploring optimal synergistic strategies for combination therapies, investigating spatiotemporally resolved immune mechanisms, and developing predictive biomarkers. These areas are currently experiencing rapid growth and require further research.