Empowering radiotherapy: Harnessing nanomedicines to enhance radiation response and boost antitumor efficacy

Radiotherapy (RT) is a conventional form of tumor treatment that uses X-ray irradiation to eliminate tumors. Although RT plays an important role in treating tumor patients and improving their survival rate, the phenomenon of tumor recurrence often occurs after RT due to the resistance of some tumor cells to radiation or the incomplete clearance of tumor tissues. A variety of factors contribute to radiation resistance in tumors, including cancer metabolism, abnormal tumor microenvironment like hypoxia, dense extracellular matrix, irregular blood vessels, and the presence of cancer stem cells. Therefore, it is crucial to clarify the causes of radiation resistance and further develop strategies to empower RT, so as to reduce RT-related adverse effects and obtain efficient therapy. This review comprehensively summarizes the causes of tumor cell radiation resistance in detail, and elucidates the use of nanomedicines to achieve the purpose of reversing radiation resistance or improving radiosensitivity of tumor cells. Furthermore, the applications of nanomedicines in the synergistic antitumor therapy of RT combined with other therapeutic modalities are also discussed. Finally, the opportunities and challenges of nanomedicines to empower RT and thus achieve complete tumor eradication in preclinical trials are presented.