Radiotherapy damages cancer cells but can also affect normal cells close by. This is what causes any side effects you get.
You usually get side effects in the part of your body that is being treated. You may also have some general side effects, such as feeling tired. Side effects usually build up during treatment. After treatment finishes, it can take a week or two before side effects start getting better. Most of them usually go away gradually after that.
Sometimes, side effects take longer to improve. Or sometimes new side effects develop months or years after radiotherapy. These are called late effects. Your specialist doctor and nurse will explain the risk of any late effects.
We have listed some possible side effects of radiotherapy below. We also have more information about radiotherapy, which is written for all age groups.
Always tell your radiotherapy team about any side effects you have or if they get worse. Your team can usually do something to improve the side effects, or they can give you more advice.