Radiation Therapy and Radiosensitizers in Cancer Treatment

Radiation therapy (RT) remains the most effective and widely used modalities in the treatment of cancer, leveraging high-energy radiation to damage the DNA of malignant cells and inhibit their proliferation. Despite its therapeutic success, the efficacy of RT can be limited by tumor resistance, hypoxia, and damage to surrounding normal tissues. To overcome these challenges, radiosensitizers agents that enhance the cancer cells’ sensitivity to radiation have emerged as a vital adjunct to radiotherapy. These agents, which include certain chemotherapeutics, molecular targeted drugs, nanoparticles, and natural compounds, work by interfering with DNA repair mechanisms, modulating cell cycle checkpoints, or reoxygenating hypoxic tumor regions. The integration of radiosensitizers has demonstrated improved therapeutic outcomes and reduced recurrence rates across various cancer types. Recent advancements in molecular oncology, nanotechnology, and precision medicine continue to optimize the design and delivery of radiosensitizers, paving the way for personalized and more effective radiation-based cancer therapies. This chapter elaborates a broad overview of principles of therapy using radiation, mechanisms of radiosensitization, and current progress in clinical and preclinical studies.