How does radiation therapy work?
Radiation therapy directly damages the DNA of cancer cells with the goal to reduce the cell division rates and induce cell death. This eventually causes the tumor to shrink. A predetermined dose – measured in the international unit Gray (Gy) – will be delivered during the whole radiation treatment. This dose is split into so called fractions in the individual treatment sessions.20
In general, cells are able to repair the damages caused by radiation exposure. However, if the radiation dose is high enough, cells of any kind can be damaged beyond repair. Different cells and tissues in the body tolerate radiation differently, which affects the amount of radiation dosage used depending on the treated body site. Many areas of the body can only tolerate a limited amount of radiation in a lifetime (maximum dosage).13
Mode of action
Cancer cells are actively growing and dividing in an uncontrolled manner, which makes them especially sensitive to radiation therapy. Due to a limited ability to repair the damaged DNA, cancer cells are more sensitive to the effects of radiation compared to normal body cells.13
Once the DNA of cancer cells is damaged beyond repair they stop dividing or die. Those dead cells are then broken down and eliminated by the body’s natural processes.