How Does Radiotherapy Destroy a Cancer Cell?

Radiotherapy simply aims to destroy the DNA of the cell by breaking it, so that the tumor cannot grow — the cancer cells die immediately or after a certain period when the cell attempts to divide. Radiotherapy affects the cancer cell and the healthy cells around it, but healthy cells are able to repair the damage because they have a system for growth and repairing any defect, unlike the cancer cell. This is what explains the gradual improvement in symptoms during the recovery period after radiotherapy.