Radiotherapy for soft tissue sarcomas
Radiotherapy treats cancer by using high-energy x-rays to destroy cancer cells, while doing as little harm as possible to normal cells.
Radiotherapy is an important part of treatment for soft tissue sarcomas, particularly those affecting the arms or legs. It’s usually given after surgery to destroy any remaining cancer cells and to reduce the risk of the cancer coming back. The wound must be healed before radiotherapy starts.
Sometimes, radiotherapy is given before an operation (neo-adjuvant radiotherapy), either to shrink the tumour and make it easier for the surgeon to remove it successfully, or to avoid having to amputate the limb.
Radiotherapy is sometimes given on its own and may be the only treatment needed. Radiotherapy is also given to relieve symptoms and control sarcomas that can’t be removed.
Radiotherapy for sarcomas is normally given as a series of short daily treatments in the hospital radiotherapy department. High-energy x-rays are directed from a machine at the area of the cancer.
The treatments are usually given from Monday-Friday, with a rest at the weekend. The number of treatments will depend on the type, size and position of the sarcoma. A course of treatment for early cancer will usually last about six weeks. Each treatment takes about 10-15 minutes. Your doctor will discuss the treatment and possible side effects with you.
Radiotherapy for sarcomas is often given using a technique called conformal radiotherapy. The radiation beams are shaped to the part of the body that needs to be treated. For some people, a more complex technique called intensity-modulated radiation therapy (IMRT) may be used. IMRT delivers a high dose of radiation to the tumour and varies the dose given to nearby healthy tissue. This can help to reduce side effects.
Planning your radiotherapy
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To make sure that the radiotherapy is as effective as possible, it has to be carefully planned. Planning ensures the radiotherapy rays are aimed precisely at the cancer and cause the least possible damage to the surrounding healthy tissues. The treatment is planned by a specialist doctor known as a clinical oncologist. Planning is important and may take a few visits.
If your sarcoma is in your arm or leg, you may need to have a plastic mould made. The mould helps to keep the limb still during radiotherapy treatment sessions. It’s made in the mould room on your first visit to the radiotherapy department. Your doctor or specialist nurse will tell you more about moulds if one is needed.
As part of the planning, you’ll have a CT scan taken of the area to be treated. At the same time, therapy radiographers will take measurements from you, which are needed for treatment planning. This session will usually take about 30 minutes.
You may also need to have an MRI scan. This uses powerful magnetic fields to give a detailed picture of part of your body, which can give additional useful information.
The radiographer’s measurements and the information from the scans are fed into the radiotherapy planning computer to help your doctors plan your treatment more precisely.
Marks may be drawn on your skin, or on the mould, to help the radiographer (who gives you your treatment) to position you accurately and to show where the rays are to be directed. These marks must stay visible throughout your treatment, but they can be washed off once your course of treatment is over. Often, very small tattoo marks are also made on the skin. These marks are permanent and will only be done with your permission. It’s a little uncomfortable while the tattoo is being made, but it’s a good way of making sure that treatment is directed accurately.
At the beginning of your radiotherapy, you’ll be told how to look after the area being treated.
At the beginning of each session of radiotherapy, the radiographer will position you carefully on the couch and make sure you’re comfortable. During your treatment you’ll be alone in the room, but you can talk to the radiographer who will watch you from the next room. Radiotherapy is not painful, but you will have to lie still for a few minutes during the treatment.
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This is a new way of giving radiotherapy that may sometimes be used to treat small soft tissue sarcomas.
Stereotactic radiotherapy treatment is given using a specially adapted radiotherapy machine, sometimes called CyberKnife, which delivers beams of radiotherapy from many different angles. The beams overlap at the tumour, giving a very high dose to it, but only a very small dose to surrounding tissues.
CyberKnife is only available in a small number of hospitals in the UK. Your specialist can give you more information if this is an option for you.
Sometimes, radiotherapy is given internally by putting radioactive material (the source) close to the tumour or the area where the tumour was before surgery. This is called brachytherapy. It’s not commonly used in the treatment of soft tissue sarcomas.
Your specialist can discuss brachytherapy and its side effects with you if they think it will be helpful.
Side effects of radiotherapy
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You may develop the side effects listed here over the course of your treatment. These side effects will usually gradually disappear over a few weeks or months after treatment is finished. Your doctor, nurse or radiographer will discuss this with you so that you know what to expect. Let them know about any side effects that you have during or after treatment, as there are often things that can be done to help.
Hair will only fall out in the area being treated by radiotherapy, so the treatment for soft tissue sarcomas will not make the hair on your head fall out. The hair that is lost may grow back after the treatment has ended, but it is often lost permanently.
Some people develop a skin reaction similar to sunburn. Pale skin may become red and sore or itchy, and darker skin may develop a blue or black tinge. Your radiographers will give you advice on how to look after your skin.
Fatigue is a common side effect and may continue for months after treatment finishes. During treatment, you’ll need to rest more than usual, especially if you have to travel a long way for treatment each day. But it’s good to do gentle exercise, such as walking, when you feel able. Once your treatment is over, gradually increase your activity and try to balance rest periods with some physical activity. This will help you build up your energy levels.
Some people find that their treatment makes them feel sick (nausea), and sometimes they may actually be sick (vomit). This is most common when the treatment area is near the stomach or bowel. If nausea and vomiting occur, they can usually be effectively treated with anti-sickness drugs (anti-emetics), which your doctor can prescribe. If you don’t feel like eating, you can replace meals with nutritious, high-calorie drinks, which are available from most chemists and can be prescribed by your GP.
Any side effects you have should disappear gradually once your course of treatment is over, but it’s important to let your doctor know if they continue.
Radiotherapy doesn’t make you radioactive and it’s perfectly safe for you to be with other people, including children, throughout your treatment.
Long-term side effects
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After radiotherapy, some people may develop swelling known as lymphoedema. This happens because the lymph nodes and vessels can become damaged by the radiotherapy. Lymph fluid, which circulates around the lymphatic system, is unable to pass along the vessels and builds up, causing swelling. If lymphoedema develops, it can’t be cured but it can often be treated and managed.
To help prevent lymphoedema, you should try to avoid getting any infection or inflammation in the area that has been treated with radiotherapy. You should try to avoid cuts or grazes in the area and use a moisturiser if your skin gets dry.
Radiotherapy to a joint, such as the knee or elbow, may cause it to become stiff. It’s important to keep the joint mobile by using it and doing regular exercise to help prevent stiffness.
A small number of people will develop a second cancer because of the radiotherapy treatment they’ve had. However, the chance of a second cancer developing is so small that the risks of having radiotherapy are far outweighed by the benefits. To reduce the risk, radiotherapy is very carefully planned and improvements in the way radiotherapy is given mean that the risk of developing a second cancer is very small.
You can talk to your cancer specialist if you’re concerned about your risk of developing a second cancer. We have more information about the side effects of radiotherapy.