Radiosensitisers

Radiosensitisers are compounds used in radiotherapy to enhance the effectiveness of radiation therapy by increasing the sensitivity of cancer cells to ionizing radiation. These agents work by either directly interacting with DNA or indirectly promoting oxidative stress, which damages cellular structures and impairs the cell’s ability to repair radiation-induced damage. By doing so, radiosensitisers can improve the therapeutic ratio, reducing the required radiation dose while minimizing damage to surrounding healthy tissue.

Commonly studied radiosensitisers include certain chemical agents, such as nitroimidazoles (e.g., misonidazole), which preferentially accumulate in hypoxic (low-oxygen) tumor regions, where radiation resistance is often higher. Hypoxia-inducible factor (HIF) inhibitors and vascular disrupting agents (VDAs) are also explored, as they target tumor vasculature to reduce oxygen supply and increase radiosensitivity. More recently, small-molecule inhibitors targeting DNA repair pathways, such as poly(ADP-ribose) polymerase (PARP) inhibitors, have gained attention due to their ability to sensitize cells to radiation by impairing DNA repair mechanisms.

Clinical applications of radiosensitisers have been explored in various cancers, including head and neck, cervical, and lung malignancies. However, challenges remain, such as toxicity to normal tissues, resistance development, and the need for precise delivery to tumor sites. Research continues to focus on identifying safer and more effective radiosensitisers, often through combination therapies with chemotherapy, immunotherapy, or targeted agents. The development of personalized medicine approaches may further optimize radiosensitizer use based on tumor biology and patient-specific factors.