Radiotherapy destroys cancer cells in the area where it is given. It can also damage some normal cells in the same area. This may cause side effects (see below).
Side effects do not usually happen straight away. They may develop during your course of treatment, or in the days or weeks after treatment finishes. After you have finished radiotherapy, side effects may get worse for a time before they get better.
You may have a small risk of long-term side effects. Side effects can sometimes also start months or years after radiotherapy. These are called late effects.
Your team will explain what to expect from treatment. But it is difficult for them to know exactly what side effects you will have. Always tell them if you have side effects during, or after, radiotherapy. They can give advice and support to help you cope.
If you smoke, try to stop. Research shows that stopping smoking during and after radiotherapy may help it work better. It can also reduce the side effects of treatment. Your radiotherapy team, GP or a pharmacist can help.
You are unlikely to get all the different side effects of radiotherapy. The side effects you have may depend on:
- the area of your pelvis having treatment
- whether you have external or internal radiotherapy
- other cancer treatments you are having, such as surgery, chemotherapy or hormonal therapy.
Having chemotherapy at the same time as radiotherapy is called chemoradiation. This may cause more severe side effects.
You may also find it helpful to read our information about the type of cancer you are having treatment for. This has more detail about your treatment, and the other possible side effects.