Side effects depend on things such as the dose of radiotherapy, whether it’s external or internal, and whether you have chemotherapy as well (chemoradiation).
Side effects usually start a week or two after starting treatment. They may continue to get worse for a couple of weeks after treatment, before beginning to get better. Side effects usually improve gradually over the next few weeks or more.
Smoking can make side effects worse. If you smoke, try to give up smoking or cut down. Drink at least 2–3 litres of fluid a day. Water is best. Drinks containing caffeine and alcohol can make bowel and bladder symptoms worse.
It’s important to tell your radiographer, cancer specialist or specialist nurse if you have side effects. They can give you advice on how to manage them and prescribe treatments that can help.
It may take some time to recover, particularly after longer courses of radiotherapy or chemoradiation. Look after yourself by getting enough rest and gradually increasing your physical activity. This will help with your recovery.
Occasionally, some side effects don’t completely go away. Sometimes, side effects develop months or years later. These are called long-term or late effects. If side effects don’t get better or you notice new side effects developing, tell your cancer nurse or doctor. There are many things that can be done to help. We have more information about coping with late effects of treatment on your bowel.