[Expert consensus on application specifications of low-dose radiotherapy in solid tumors (2026 edition)]

Low-dose radiotherapy (LDRT), as an emerging tumor immunomodulatory strategy, has demonstrated its synergistic anti-tumor potential when combined with immunotherapy in multiple solid tumors. Unlike traditional high-dose radiotherapy that directly kill tumors, LDRT reshapes the tumor immune microenvironment by promoting dendritic cell antigen presentation, enhancing T-cell infiltration, reversing the immunosuppressive microenvironment, and remodeling tumor vascular and stromal structures, thereby enhancing the efficacy of immunotherapy. Clinical studies have shown that LDRT combined with immune checkpoint inhibitors, chemotherapy, or high-dose radiotherapy can increase the objective response rate and improve patient survival in solid tumors such as non-small cell lung cancer, extensive-stage small cell lung cancer, and head and neck squamous cell carcinoma, with favorable safety profiles. However, unified standards for LDRT are still lacking in terms of patient selection, combination strategies, dose fractionation, sequencing, and target volume delineation. Based on current basic research and clinical evidence, this expert consensus, titled "Expert consensus on application specifications of low-dose radiotherapy in solid tumors (2026 edition)", systematically elaborates on the mechanisms, clinical applications, and recommended regimens of LDRT, aiming to promote its standardized application and providing a reference for future clinical research and practice.