Ionising radiation damages the DNA of tumour cells, preventing them from dividing and causing them to die. Healthy cells surrounding the tumour are better able to regenerate – and radiotherapy exploits this difference.
Modern radiotherapy techniques such as IMRT (intensity-modulated radiotherapy) or stereotactic radiotherapy allow for extremely precise dose distribution: high doses to the tumour, with minimal exposure to surrounding tissue.
Curative vs. palliative radiotherapy: Curative therapy aims to cure the disease. Palliative therapy aims to control symptoms and improve quality of life – for example, in cases of bone or brain metastases.