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Prophylactic cranial radiotherapy (PCR) is used to prevent or delay the spread of a cancer to the brain. It is also sometimes called PCI, which stands for prophylactic cranial irradiation.
This information describes PCR, when and how it is given along with the possible side effects. It should ideally be read with our information about radiotherapy|.
We hope this infomation answers your questions. If you have any further questions, you can ask your nurse or doctor at the hospital where you're having treatment.
Prophylactic cranial radiotherapy is when radiotherapy (x-ray treatment) is given to a person’s head to prevent or delay the spread of a cancer to the brain (secondary brain cancer|). Prophylactic means preventative and cranial refers to the head.
PCR is usually given to people who have a type of lung cancer called small cell lung cancer (SCLC)|. It may occasionally be given to people with acute lymphoblastic leukaemia (ALL)|. PCR may also help reduce the risk of secondary brain cancer in people who have non-small cell lung cancer (NSCLC)|, but this is still being researched.
People with SCLC may have PCR when the cancer has not spread to other parts of the body, and has responded well to previous treatments. With SCLC, there is a risk that tiny numbers of cancer cells may escape from the lung and spread to the brain. These would be too small to be detected by scans but in time would grow to form secondary cancers in the brain. Your specialist may recommend PCR to prevent this happening. PCR treats the whole brain.
PCR may be more effective than chemotherapy| at treating cancer cells that may have spread to the brain. This is because the brain is protected by a membrane called the 'blood-brain barrier' that stops a lot of chemotherapy drugs from getting to the brain.
PCR may also be useful for people with SCLC who have more advanced disease. Your specialist can advise you whether PCR is an appropriate treatment for you.
When PCR is given to those who are in complete remission from SCLC, and have no signs of the cancer, studies show that it helps people live longer. It reduces the chance of developing a secondary cancer in the brain.
PCR may occasionally be given to people with ALL, if it’s thought that they may be at risk of the leukaemia affecting the brain.
Radiotherapy treats cancer by using high-energy rays that destroy cancer cells while doing as little harm as possible to normal cells. PCR aims these high-energy rays at the head and is given by a radiotherapy machine. This is known as external beam radiotherapy. The treatment is given in the hospital radiotherapy department.
Your radiotherapy is carefully planned to make sure that you get the maximum benefit. This may involve a few visits to the radiotherapy department before treatment starts. As radiotherapy is planned very precisely to treat exactly the right area, it’s important to keep that part of the body as still as possible. You’ll be asked to lie back with your head on a firm headrest. A soft clamp may be fitted to each side of your head to hold it steady during treatment.
Alternatively, a see-through perspex device or a plastic mesh| may be used to make a mould that fits around your head. The mould is used to help you stay in position during radiotherapy.
PCR is given as a series of short daily treatments (sometimes called fractions) in the radiotherapy department, using equipment similar to a large x-ray machine. Each treatment lasts for only a few minutes. The treatments are usually given from Monday–Friday, with a rest at weekends. The number of radiotherapy sessions will vary depending on your situation.
Each person’s reaction to radiotherapy is different. Some people have very few side effects while others may experience more. Usually the side effects of PCR are mild. If you notice any effects that you think may be due to PCR but are not listed below, let your doctor, nurses or radiographers know.
Your hair may start to fall out about three weeks after your first treatment. Most hair loss| is temporary. Hair usually starts to grow back 2−3 months after you finish treatment. Sometimes it grows back with a slightly different colour and texture, and it may not be as thick as before.
You may find that you feel very tired| during radiotherapy. This can often be made worse by having to travel to hospital each day. Listen to your body and allow yourself extra time for a nap during the day. Tiredness may continue for about three months after treatment has finished.
This can occur throughout your radiotherapy and for a time after the treatment has finished. It is usually mild. Drowsiness is at its worst about two weeks after treatment starts, but will gradually begin to improve. It can sometimes get worse again around 4−6 weeks after treatment finishes, but it will get better a week or so later.
Occasionally, some people experience headaches during treatment. This usually happens in the first few days after starting PCR. It's important to let the staff looking after you know if you have a headache. Your doctor may prescribe painkillers| and sometimes steroid tablets|.
You may feel sick (nausea|) but this is uncommon and can usually be effectively treated with anti-sickness (anti-emetics) drugs. Your doctor can prescribe these. If your sickness isn't controlled, or if it continues, tell your doctor; they can prescribe other anti-sickness drugs that may be more effective.
You may find that food tastes different|. If you don’t feel like eating, you can replace meals with nutritious, high-calorie drinks|. These are available from most chemists and can also be prescribed by your GP. A dietitian or specialist nurse at your hospital can give you advice.
Some people have a skin reaction while having external radiotherapy. With PCR, any skin changes are usually mild, but your skin may become sore behind the ears. People with pale skin may find that the treatment area becomes red, hot, sore or itchy. People with dark skin may find that their skin becomes darker. The degree of any skin reaction depends on the area being treated and your skin type. Staff in the radiotherapy department will be checking for any reaction, but let them know if you notice any changes or feel any soreness.
The staff will also be able to give you advice on skincare. This may vary from one hospital to another and depend on the dose of radiotherapy that is being given. You might be advised not to wash the treatment area at all while you are having treatment. Or you may be told that it's best to use only tepid water and to dry yourself by patting gently with a soft towel and not rubbing.
Because your skin will be sensitive during and after treatment, it's best not to over-expose it to the sun or cold winds. Try wearing a soft cotton or silk scarf, or a hat to cover your head when you go outside. It’s also important to cover the treated area if you go out in strong sunshine for at least the first year after radiotherapy.
You may find the idea of radiotherapy to the head worrying. You may have many different emotions| including anger, resentment, guilt, anxiety and fear. These are all normal reactions, and are part of the process many people go through in trying to come to terms with their condition.
People often worry that PCR may affect their memory or their ability to think clearly, but this is very unlikely with the low doses of radiotherapy used for PCR. It can be useful to discuss any worries you have with your doctors or nurses.
Everyone has their own way of coping with difficult situations. Some people find it helpful to talk to family or friends, while others prefer to seek help from people outside their situation. Some people prefer to keep their feelings to themselves. There is no right or wrong way to cope, but help is there if you need it. Our cancer support specialists| can give you information about counselling in your area.
This information has been compiled using information from a number of reliable sources, including:
With thanks to Dr David Gilligan, Consultant Clinical Oncologist, and the people affected by cancer who reviewed this edition. Reviewing information is just one of the ways you could help when you join our Cancer Voices network|.
Content last reviewed: 1 January 2013
Next planned review: 2015
For answers, support or just a chat, call the Macmillan Support Line free (Monday to Friday, 9am-8pm)
If you have any questions about cancer, need support or just want someone to talk to, ask Macmillan.
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© Macmillan Cancer Support 2013
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