Why is radiotherapy given?

Curative treatment
Radiotherapy is often prescribed with the aim of destroying the tumour, and, it is hoped curing the cancer. When radiotherapy is given in this way it is described as radical radiotherapy. Radiotherapy may be given before or after surgery or before or after chemotherapy (the use of anti-cancer drugs to destroy cancer cells). If radiotherapy and chemotherapy are given at the same time, this treatment is known as chemoradiotherapy.

Palliative treatment
Sometimes, when it is not possible to cure a cancer, radiotherapy may be given to relieve symptoms – for example, to lessen pain. This is called palliative treatment. Lower doses of external radiotherapy are given than for curative treatment, usually over a shorter period of time (sometimes just a single treatment).

Total body irradiation
This type of radiotherapy is used much less commonly than the other types of radiotherapy, but is often given to patients who are having a bone marrow or stem cell transplant for example, as treatment for leukaemia. A large single dose, or six to eight smaller doses of radiation is given to the whole body to destroy the cells of the bone marrow. Very high doses of chemotherapy are also given, followed by new bone marrow given by a drip into a vein, to replace the bone marrow that has been destroyed. This type of radiotherapy is described in the section on stem cell and bone marrow transplants