Brain cancer: Understanding late effects of radiotherapy
Late side effects may happen a few months or years after treatment. They might happen once, carry on for a long time or come and go. Sometimes they cannot be cured, but it might be possible to manage them. or reduce their impact.
You might have late effects not listed here, because everyone is different. They may also be caused by a different part of your cancer treatment. It is not possible to predict if you will get them and when they might happen, which can be difficult to come to terms with. Research and support for late effects of radiotherapy is growing.
Joining a support group can be a positive way to share your experiences, feel less alone, and come to terms with the physical and emotional impact of treatment. Ask your clinical team if you need more support or want to talk about your late effects.
This page looks at late side effects.
How likely am I to get late side effects?
Before treatment you will discuss and sign a consent form with your clinical oncologist or therapeutic radiographer. They will tell you what your chances are of getting early or late side effects and you can ask questions or raise concerns.
When you consent to treatment by signing the consent form, you are confirming you understand there is a chance of getting late side effects. Your team will use words like Expected, Common, Less Common and Rare.
This table shows what these words mean.
| Wording on the consent form | % chance of side or late effect | How many patients will get this? |
| Expected | 50 to 100% | Between half and all patients |
| Common | 10 to 50% | Up to half of all patients |
| Less common | Less than 10% | Fewer than one in ten patients |
| Rare | Less than 1% | Fewer than one in 100 patients |
Possible late side effects
- Somnolence syndrome: Some people might feel very tired, irritable, have headaches, sickness and lose their appetite (not feel like eating). This can happen 1 to 6 months after treatment but usually goes away after a few weeks. Medicines can help if needed.
- Problems with thinking and memory: Sometimes, people might have trouble thinking clearly or remembering things. which may be progressive and worsen with time. This can also happen after surgery or chemotherapy.
- Eye problems: Radiation can cause the lens in your eye to become cloudy (a cataract), making it hard to see. This can happen years later, but doctors can fix it with a small operation.
- Hearing problems: Over time, you might slowly lose your hearing or get ringing in your ears. Hearing aids can help if this happens.
- Pituitary gland issues: The pituitary gland (which helps control many body functions) might not work well after radiation. Doctors can check your blood and give you medicines if needed.
- Permanent hair thinning or loss around treatment area.
- Worsening or onset of seizures (epilepsy), which may require long term treatment with anti-seizure medication.
- Changes to balance, dizziness or co-ordination.
Rare or less common late effects
- Brain tissue damage: In rare cases, high doses of radiation can cause brain tissue to change permanently after treatment (radionecrosis). This may require treatment like steroids or surgery.
- Second Cancer: There is a very small chance that you could develop another type of cancer. This small risk is also from all the X-rays and scans you have had over your life, and natural exposure to radiation around us. The chance of this happening is about 0.5 – 1% over 10 years.
- Brain, brainstem or spinal cord injury which could result in permanent disability
- Stroke or mini stroke
- Stroke-like migraine attacks (SMART)
- Eye problems: Other changes to the eye might cause vision loss and are usually not reversible. This is rare.
What can help with these late effects?
- Keeping active: Gentle movement can help you feel better, both during and after treatment. Your treatment team can tell you what is safe for you to do.
- Eye care: Regular check-ups with an eye doctor (opthalmologist) and treating other health problems like diabetes can help protect your vision. If you get a cataract, surgery can fix it.
- Hearing care: Hearing aids can make it easier to hear if you have hearing loss.
- Hormone replacement: If your pituitary gland is affected, hormone medicines can help.
- Managing cancer-related fatigue: Food and drink, keeping active, keeping a fatigue diary, medicine like steroids and physiotherapy may all be options for managing fatigue. Speak to your doctor or clinical team for advice.
- Monitoring rare side effects: Talk to your treatment team as soon as you notice any changes, this can help catch and treat any serious problems early.
- Managing cancer-related fatigue: Food and drink, keeping active, keeping a fatigue diary, medicine like steroids and physiotherapy may all be options for managing fatigue. Speak to your doctor or clinical team for advice.
- Drinking fluids: Drinking plenty of fluids such as water and squash can help with fatigue and tiredness caused by your treatment. It can also help flush out toxins in your body caused by treatment. You can try diluted juice if you don’t like water.
- Skin care: The skin in the treatment area will always be more sensitive to the sun. Always protect it by covering up and use a high factor sunblock.
- Alcohol use: Please follow the NHS guidelines on safe drinking levels and any instructions you get from your team on what is right for you, your diagnosis and your treatment. If in doubt, please ask your team.
- Stop smoking: If you are looking to stop or reduce smoking, there are services available to help you. Please see the links at the bottom of this page for more information.
Always talk to your doctor or treatment team about any late effects you have. Even if they are not mentioned here. Everyone is different and experiences treatment differently. There may be ways they can help you reduce or manage symptoms.
Further information
Find further support for patients here:
Learn more about Gamma Knife radiotherapy for brain tumours:
Understanding Gamma Knife radiotherapy (VIDEO SERIES) • Radiotherapy UK
Learn more about radiotherapy consent forms here:
https://www.rcr.ac.uk/our-services/management-service-delivery/national-radiotherapy-consent-forms/
Learn more about radiation skin reactions here:
Learn more about managing cancer fatigue:
Managing and treating cancer fatigue | Cancer Research UK
Cancer-related fatigue | NHS inform
Learn more about tools and techniques for managing sex after cancer treatment:
Sex and cancer | Impact on your sex life and relationships | Macmillan Cancer Support
Advice and support on reducing alcohol use:
Drink less – Better Health – NHS (www.nhs.uk)
NHS stop smoking services:
