17133 Intensity Modulated Radiation Therapy

Overview

Intensity-modulated radiation therapy (IMRT) is a modern, precise form of radiotherapy. Radiotherapy uses high-energy X-rays to damage cancer cells so they can no longer grow and divide. In IMRT, the radiation machine moves around you and the strength of each beam can be adjusted in small sections. This lets your treatment team shape the radiation to match the exact outline of the area being treated while keeping the dose as low as possible to nearby healthy parts, such as the bladder, bowel, spinal cord or salivary glands. IMRT is a treatment technique, not a disease or a condition in itself. Your doctor may suggest it if you need radiotherapy and a very precise, shaped dose would be helpful.

Yes. IMRT is now one of the most widely used forms of radiotherapy in many countries, and it is offered in most major cancer centres.

IMRT is used for people of all ages who need radiotherapy. It is often chosen for cancers in areas where nearby healthy tissue matters a lot — for example head and neck, prostate, breast, lung, pelvic and brain tumours — and sometimes for non-cancerous growths. Children may have it too, with extra planning and support to help them stay still during treatment.

Symptoms

Common symptoms

• Tiredness (fatigue) that builds up over the course of treatment
• Skin changes in the treated area — redness, dryness, itching, or soreness like mild sunburn
• Soreness, discomfort or swelling in the area being treated
• Hair loss, but only in the part of the body being treated
• Depending on the area treated: a sore mouth or throat, changes in taste, a dry mouth, feeling sick, loose stools, or needing to pass urine more often
• A lower appetite, and sometimes low mood or worry

Symptoms in children

• Tiredness and skin changes in the treated area, as in adults
• Young children often need a light general anaesthetic or sedation to lie still during treatment, which can leave them sleepy afterwards
• Children may find the mask, noises and machine frightening, so play therapy and a parent staying close are usually arranged
• Growth, learning and hormone effects are watched closely by the children's cancer team when the brain or spine is treated

Symptoms in older adults

• Fatigue can feel more intense, especially if there are other health conditions
• Skin reactions may take a little longer to heal
• Extra support may be needed with travel to daily appointments and with meals and hydration
• A review of other medicines is usually helpful, since some can make side effects worse

Causes

Main causes

• IMRT is not caused by anything — it is a treatment you are given, not a condition you catch
• It is used to treat many kinds of cancer, including head and neck, prostate, breast, lung, bowel, bladder and brain tumours
• It may also be used to treat some non-cancerous growths where precise dosing matters
• Sometimes it is given on its own, and sometimes alongside surgery, chemotherapy or other treatments

Risk factors

• A larger area being treated, or treatment close to sensitive organs, can mean more side effects
• Having chemotherapy at the same time can make side effects stronger
• Smoking can slow healing and worsen mouth and throat reactions
• Being underweight, dehydrated or poorly nourished before treatment can make recovery harder
• Other long-term health conditions, such as diabetes or heart disease, can affect how well you cope

When to see a doctor

See a doctor urgently if:

• You have a fever of 38°C (100.4°F) or higher, or you feel shivery and unwell
• You cannot keep fluids down, or you have diarrhoea many times a day
• You have severe pain that your usual pain relief does not touch
• The skin in the treated area blisters, breaks open or starts to weep
• You feel confused, very drowsy, or much weaker than before

Book a routine appointment if:

• Skin redness or itchiness in the treated area is getting worse
• You are losing weight or struggling to eat or drink
• Tiredness is affecting your daily life and you would like help managing it
• You feel low, anxious or overwhelmed
• You have any new symptom that worries you, even if it seems small — your treatment team would much rather hear about it

Diagnosis

IMRT is not something you are diagnosed with — it is planned for you after your cancer team has confirmed what needs treating, usually from earlier scans and a biopsy. The first step in planning is often called 'pre-treatment planning' or the 'planning scan'. You lie in the same position you will be treated in, often with a soft support or a moulded mask, and a CT scan is taken. The team then uses special software to draw the exact shape of the area to treat and the healthy parts to avoid, and works out the best beam angles and strengths. This can take several days.

Tests that may be done

• A planning CT scan, taken lying in your treatment position
• Sometimes an MRI or PET scan to help map the area more precisely
• Blood tests to check your general health before treatment starts
• A dental check-up before head and neck treatment, to prevent problems later
• Fitting of a mask, mouthpiece or other support to keep you still during each session
• A 'dry run' or verification scan to check the position is accurate before the first real treatment

What to expect at your appointment

Your planning appointment usually takes longer than a treatment session, sometimes an hour or more. You may be asked to come with a full or empty bladder for pelvic treatment, depending on your plan. Someone will explain what will happen step by step. If you feel nervous, say so — the team can talk you through it and take things slowly.

Treatment

IMRT is given by a machine called a linear accelerator. You lie on a treatment couch, often with a moulded support, and the machine moves around you without touching you. Each session is painless and usually takes around 10 to 30 minutes, most of which is spent getting you into exactly the right position. You will usually attend daily, Monday to Friday, with a rest at weekends, for several weeks — your team will tell you your own schedule. Radiotherapy does not make you radioactive and it is safe to be around other people, including children and pregnant women, after treatment.

Self-care at home

• Treat the skin in the treated area gently: wash with lukewarm water and a mild, unperfumed product, pat dry, and do not scrub, shave closely or use perfumed creams unless your team agrees
• Keep the treated area out of strong sun and avoid heat packs, hot water bottles and tight clothing over it
• Get plenty of rest, and plan short rests during the day if tiredness builds up
• Drink enough fluid each day, and eat small, frequent meals if your appetite is low
• Keep doing gentle everyday movement, and ask your team about specific exercises if you have shoulder or neck treatment
• Tell your team about any side effect early — they have practical treatments and advice ready
• Keep a written note of your appointments, side effects and questions, so you remember them at reviews

Medical treatments

IMRT itself is the treatment. Alongside it, your care team may offer other approaches to help: creams or dressings for skin reactions, medicines to settle nausea, pain relief, mouthwashes or saliva substitutes for a dry or sore mouth, and advice on softening stools. Side effects that affect eating may be helped by a dietitian, and some people need fluids through a drip. Your oncology team will tailor any prescribed medicines to you and monitor you at regular reviews. Always check with your team or pharmacist before taking anything new, including herbal remedies and supplements, as some can interfere with treatment.

When is surgery considered?

Surgery is a separate treatment and is used when removing the tumour is the right option — sometimes before radiotherapy, sometimes after it. Your team will explain whether surgery is part of your plan and in what order. IMRT is often used after surgery to reduce the chance of the cancer coming back, or instead of surgery when an operation is not suitable.

Living with this condition

Many people manage to keep working and doing normal things during IMRT, though you may need to slow down and plan rest. The daily trips to the hospital can be tiring in themselves, so it helps to accept offers of lifts or help with shopping and meals. Side effects usually build up gradually over the weeks and are often at their strongest towards the end of treatment and for a week or two afterwards, before they start to improve. Your team will tell you what to expect for your particular treatment area.

Lifestyle tips

• Keep to a simple routine and protect time for rest
• Avoid smoking and cut down on alcohol, which can worsen mouth, throat and skin reactions
• Ask about gentle exercise — short walks can help with fatigue and mood
• Use a soft toothbrush and keep up gentle mouth care if your mouth or throat is being treated
• Note any skin products or soaps your team recommends, and stick to them
• Ask your employer about flexible hours or a phased return if you are working

Diet and exercise

Eat regular, balanced meals with enough protein to help your body repair itself — eggs, beans, fish, chicken, dairy or plant alternatives all count. If your appetite is small, eat little and often, and ask your team about meal-replacement drinks. Keep fluids going throughout the day. Gentle movement, like a short daily walk, is usually encouraged and can ease tiredness, but build rest around it. A dietitian and physiotherapist can give you a plan suited to your treatment area.

Mental health and emotional wellbeing

It is very common to feel anxious, low, or simply worn out during radiotherapy, and the daily routine can feel like a lot to carry. You may worry about results, about money, or about family. These feelings are understandable and there is real help available — talking to your treatment team, a counsellor, or a support group often makes a big difference. If you ever feel hopeless or have thoughts of harming yourself, please reach out straight away: contact your doctor or treatment team, or call your local emergency number, or your local crisis or mental health helpline, which you can find through your doctor or local health service.

Prevention

IMRT is a treatment, so it is not something you can prevent. What you can do is prepare well for it — stopping smoking, eating well, keeping hydrated and telling your team about side effects early all help you get through treatment as comfortably as possible. Many cancers that are treated with radiotherapy can be found earlier through screening programmes, which is why attending screening when invited matters.

Screening programmes

Screening programmes vary by country and usually cover breast, bowel and cervical cancer, with some countries also offering lung screening for people at higher risk. Your local health service can tell you what you are eligible for and when your next screening is due.

Complications

If left untreated

• Without IMRT or another effective treatment, the cancer it is aimed at may keep growing and could spread to other parts of the body
• Some non-cancerous growths may also cause problems if left untreated, depending on where they are
• These are general points — your own team can explain what is likely in your situation and what the alternatives are

Long-term outlook

The outlook depends on the type and stage of the cancer being treated, and IMRT is used with the aim of curing many cancers or of controlling them for a long time. IMRT is designed to give the best dose to the cancer while protecting healthy tissue, which can mean fewer long-term problems than older techniques. Side effects are usually temporary, though some — such as a dry mouth or changes in bowel or bladder habits — can last longer. Your team will talk honestly with you about what to expect, and there is support at every stage.

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