Side effects of radiotherapy for brain tumours
Radiotherapy to the brain can cause short term side effects such as tiredness and sickness. These side effects usually improve a few weeks after treatment. You may also have long term side effects which can continue for a lot longer and sometimes might be permanent.
These side effects vary from person to person. They also depend on what other treatment you are having. For example, your side effects could be worse if you are also having chemotherapy.
You may not have all of the effects mentioned. Side effects can include:
You might feel tired during your treatment. It tends to get worse as the treatment goes on. You might also feel weak and lack energy. Rest when you need to.
Tiredness can carry on for some weeks after the treatment has ended. But it usually improves gradually.
Various things can help you to reduce tiredness and cope with it, such as exercise. Some research has shown that taking gentle exercise can give you more energy. It's important to balance exercise with resting.
Somnolence syndrome
In a few people, tiredness can become very severe within 5 to 6 weeks after the treatment finishes. This is called somnolence syndrome. You might also have other symptoms such as loss of appetite.
Somnolence syndrome is more common in children, but can also happen in adults. It doesn't need treatment and gets better on its own over a few weeks.
Radiotherapy to the brain can cause hair loss or thinning. If you are having treatment to a particular part of the head, your hair usually falls out in that area. You might also have some hair loss on the opposite side of the head, where the radiotherapy beams pass through. This area is called the exit site.
Whether or not your hair grows back depends on the type of radiotherapy you're having. For example, if you're having radiotherapy to treat your symptoms, it's likely that your hair will grow back. Whereas treatment to try to cure your cancer uses a high dose of radiation and so permanent hair loss is much more common.
You might like to cover your head with a soft hat, scarf or wig until your hair grows back.
You might feel sick during treatment and for a few weeks after the treatment has finished. Sickness is usually well controlled with medicines. Your treatment team can give you anti sickness tablets. Some people find that it helps to take them 20 to 60 minutes before having treatment.
Your doctor might also give you steroids. Radiotherapy to the brain can cause swelling which can lead to nausea. Steroids can help to reduce swelling and sickness.
Radiotherapy for brain tumours can sometimes make symptoms worse before they get better. This is because the treatment can cause swelling in the brain. The swelling increases the pressure in the head and makes the symptoms worse.
This can be frightening because you might think the radiotherapy isn't working. Increased pressure in the brain might cause:
- headaches
- feeling sick
- fits (seizures)
You usually take steroids during treatment to help with this.
Radiotherapy can cause many different side effects, such as tiredness. The side effects you get will depend on the area you're having treatment to but there are some general side effects you might experience regardless of where your cancer is. This video is about the side effects you might have when having radiotherapy to the brain.
On screen text: Severe tiredness (somnolence)
Mary: You know, when you say you're tired, it's not like being tired. It's like you lose all of your energy and you just do something simple like having a shower and it's like you have to lie down or you have to rest.
Martin (radiographer): After completing brain radiotherapy, you may experience severe tiredness known as somnolence. This can occur about six weeks after treatment finishes.
Mary: That fatigue really hit me and it went on for a while afterwards as well. It didn't get worse. It just stayed.
Martin (radiographer): Symptoms of somnolence include extreme tiredness and slowed mental processing. To help you cope we would recommend listening to your body and trying not to overdo things but if you can do light exercise to help maintain your energy levels.
Mary: I just took a rest if I needed to and I had to learn not to be so hard on myself. But there is little things that you can do that I felt helped anyways. That little bit of exercise. Just going for them small walks. They really do help you and even if it is just walking around your house or just walking around the block, getting outside, just getting a bit of fresh air that really, really did help me.
On screen text:
- Rest and have short naps when you need to
- Drink plenty of water
- Eat a balanced diet
- Do some gentle exercise
- Try to get some fresh air
On screen text: Feeling or being sick
Mary: After the first two or three days of the radiotherapy, I started getting really bad nausea. As the radiotherapy went on, it was just kind of a constant. Every time I'd have it, I'd feel sick afterwards.
Martin (radiographer): If you do experience sickness, then speak with your team. They can prescribe medications to help with that.
Mary: I did ask my oncologist. I'll just explain to him that I'm feeling sick from this. Please, can I get something? And then they did. They prescribed me these anti sickness medication so that did help me a lot. You don't want to eat anything, but you have to. If you're going to keep your strength up, anything that aggravates your stomach or aggravates the nausea, don't go near that but if you don't eat even though you feel sick and you feel nauseous, then you're going to feel even worse.
On screen text:
- Ask your doctor about anti sickness medication
- Your doctor might prescribe you steroids to help with your sickness
- Relaxation techniques such as mindfulness and visualisation can help
- Certain food might make it worse, such as fried food
- Eat a few hours before treatment rather than just before
- Try sipping water or fizzy drinks throughout the day
On screen text: Hair loss
Martin (radiographer): Having radiotherapy to your head can cause hair loss in the area that we're treating. It's unlikely to be all over the head, more likely to be in patches.
Mary: 2 to 3 weeks after the radiotherapy I was brushing my hair and loads came out on the brush. I knew it was going to happen, but it was just hard when it happened.
Martin (radiographer): In many cases, the hair will grow back about two months after treatment finishes. The texture and the colour may be different to before.
Mary: Mine did grow back and there's a lot of grey in it so I have to dye it, this is not my original colour. It's very slow growing back. I would say use quite a sensitive shampoo, a baby shampoo. Use that for sensitive skin in your head.
Martin (radiographer): Protect the head from the sun and the wind and avoid using hair colour, hair dryer or straighteners to style your hair. If you experience substantial hair loss, then speak with your team who can give you information about wigs and hair coverings.
Mary: I got some really cool head scarves. There is some really nice ones out there.
On screen text:
- Be gentle with your hair
- Use a non-perfumed shampoo or baby shampoo
- Avoid using heat on your hair such as a hairdryer or hair straighteners
- Let hair dry naturally or gently pat dry with a soft towel
- Your radiographer can advise you on how to care for sore skin
- Speak to your radiographer about hair coverings and wigs
On screen text: Your symptoms might get worse
Martin (radiographer): Radiotherapy to the brain can cause swelling in the area that we're treating. If you already had symptoms before starting treatment, this swelling may make the symptoms worse. After you've finished treatment, the swelling may continue for a few more weeks, but then you should recover quite quickly.
On screen text:
- Your symptoms may get worse during treatment
- This might include headaches, sickness, fits, numbness and weakness in your hands and feet
- You might need steroids to help reduce the swelling
If you're experiencing a side effect that hasn't been covered in this video, you can find more information on the Cancer Research UK website.
On screen text: For more information go to: cruk.org/radiotherapy/side-effects
Side effects of stereotactic radiotherapy and radiosurgery
Stereotactic radiotherapy and radiosurgery isn’t suitable for everyone. It targets the radiation very precisely at the tumour, which means that the tumour receives a high dose of radiation and the tissues around it receive a much lower dose. So the treatment tends to have fewer or milder side effects, than regular radiotherapy to the brain.
Side effects include:
- tiredness
- feeling sick
- headaches
- feeling dizzy
- a patch of hair loss
There is also a small risk of fits (seizures) after radiosurgery. Because of this, the Driver and Vehicle Licensing Authority (DVLA) don't allow you to drive for at least a month after treatment. You must also notify the DVLA.
Long term side effects
Most side effects gradually go away in the weeks or months after treatment. But some can continue, or start some months or years later.
Long term side effects won't happen to everyone. It's important to remember that the benefits of the radiotherapy usually far outweigh the risks.
Radiotherapy machines have improved a lot recently. So long term side effects are less common now than they were a few years ago. Side effects can include:
Radiation can cause changes in the brain tissue. Blood vessels may slowly become scarred and blocked, reducing the blood supply to some areas of the brain. This can have an effect on your brain function. Symptoms of this include:
- problems thinking clearly
- difficulty managing tasks that you previously found easy
- poor memory
- confusion
- headaches similar to migraines that come and go (this is sometimes called the SMART syndrome)
You might also have symptoms similar to those you had when you were first diagnosed.
Your doctor may suggest that you have an MRI scan or a PET scan to find out whether your symptoms are caused by changes in the brain tissue or by tumour cells.
Over a period of time, the treated area might develop a small area of dead cells. This is called radiation necrosis.
Radiation necrosis usually happens 1 to 3 years after the treatment finishes. It is more common in people who have had a high dose of radiation to a small area of the brain (radiosurgery).
Most people don't have symptoms and do not need treatment. A small number of people might develop symptoms that depend on the area of the brain affected. If this is the case, you may have treatment with steroids or an operation to remove the affected area.
You might have changes in the levels of certain hormones if you have had treatment near your pituitary gland.
For example, you might have thyroid problems or low levels of the hormone cortisol. You usually have blood tests to check for this. Your doctor can give you replacement hormones to take if you have changes in the levels of hormones.
In very rare cases, you may develop another brain tumour many years after you were first treated. This is because, although radiation kills cancer cells, it is also a risk factor for developing them.
Unfortunately, tumours caused by previous radiotherapy tend not to respond very well to treatment. The tumours might be high grade and grow more quickly.
Talk to your treatment team if you are worried about developing a second cancer in the future.
You might develop a cataract in the lens of your eye if you have radiotherapy close to your eye. Cataracts can make your vision cloudy, blurred or dim.
You can usually have a small operation to treat cataracts.
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