- Radiation therapy is a cornerstone of modern cancer treatment, using high‑energy electromagnetic or particle radiation to destroy malignant cells while preserving surrounding healthy tissue as much as possible. It is one of the most widely used oncological interventions, applied either alone or in combination with surgery, chemotherapy, immunotherapy, or targeted therapies. Radiation therapy works by damaging the DNA of cancer cells, preventing them from dividing and ultimately leading to cell death. More details on related concepts can be explored through ionising radiation and DNA damage mechanisms.
- Radiation therapy relies on the biological principle that cancer cells have impaired DNA repair pathways and divide more rapidly than normal cells. When exposed to ionising radiation, cancer cells accumulate lethal DNA breaks, particularly double‑strand breaks. Healthy cells can often repair this damage, but malignant cells cannot, making them more susceptible to radiation‑induced death. This selective vulnerability forms the foundation of therapeutic radiation. The effectiveness of treatment depends on dose, fractionation schedule, tumour oxygenation, and intrinsic radiosensitivity.
- There are two major forms of radiation therapy: external beam radiation therapy (EBRT) and brachytherapy. EBRT uses linear accelerators to deliver high‑energy X‑rays, gamma rays, or particle beams (such as protons) from outside the body. Modern EBRT techniques, including intensity‑modulated radiation therapy (IMRT) and stereotactic body radiotherapy (SBRT), allow precise targeting of tumours with minimal exposure to surrounding tissues. Brachytherapy involves placing radioactive sources directly inside or near the tumour, providing high local doses with rapid fall‑off. More details on treatment modalities can be explored through radiotherapy techniques.
- Radiation therapy is used to treat a wide range of cancers, including breast, prostate, lung, head and neck, cervical, and brain tumours. It can be curative, palliative, or used to shrink tumours before surgery. In some cases, radiation therapy is combined with radiosensitising agents that enhance tumour response. Proton therapy, a specialised form of particle radiation, offers improved dose distribution and is particularly useful for paediatric cancers and tumours near critical structures.
- Despite its effectiveness, radiation therapy can cause side effects due to unavoidable exposure of healthy tissues. Acute effects include skin irritation, fatigue, mucositis, and inflammation of the treated area. Long‑term effects may involve fibrosis, organ dysfunction, or secondary malignancies, although modern techniques significantly reduce these risks. The severity of side effects depends on dose, treatment area, and individual patient factors. More details on biological effects can be explored through radiation‑induced tissue injury.
- Advances in imaging, treatment planning, and delivery systems continue to improve the precision and safety of radiation therapy. Adaptive radiotherapy, real‑time tumour tracking, and AI‑assisted planning are transforming clinical practice. These innovations allow clinicians to tailor treatment to tumour biology, patient anatomy, and daily physiological changes, improving outcomes and reducing toxicity.
- Overall, radiation therapy remains a vital component of cancer management. Its ability to selectively damage malignant cells, combined with modern precision technologies, makes it one of the most effective and versatile tools in oncology. As research progresses, radiation therapy will continue to evolve toward more personalised, targeted, and biologically informed treatment strategies.
