Stereotactic ablative radiotherapy (SABR)

SABR may be used to treat:

• a cancer that started in the lung (primary lung cancer) that is small in size
• a cancer that has spread to another part of the body, such as the lung, liver, lymph nodes or spine – your doctor will give you more information about this
• a type of cancer that started in the liver called hepatocellular carcinoma
• some prostate cancers
• some pancreatic cancers – this may be as part of a clinical trial
• certain types of cancer when you cannot have surgery.

It may be used to re-treat areas of the body that have already been treated with radiotherapy. Sometimes if you have already had radiotherapy it is not safe to have it to the same area again. SABR is so precise it means you may be able to have it to an area already treated with radiotherapy.

SABR is not suitable for everyone. Whether it is suitable for you depends on:

• where in the body the cancer is
• the size of the cancer
• whether the cancer has spread to other parts of the body from where it started.

Your doctor can talk to you about whether it is a treatment option for you.

Planning your treatment is an important part of SABR. You may need to visit different departments in the hospital before starting your treatment.

It is important to tell the hospital staff about any medications and allergies you have. If you take painkillers, they may advise you to take them before your planning and treatment. This can make you more comfortable.

You may need to have a mould or radiotherapy mask made before radiotherapy planning starts. This is to help you stay still and in the correct position during your treatment. The radiographer may use moulds to keep a leg, an arm or other body part still during planning and treatment. Radiotherapy masks may be used for people having radiotherapy to the brain, head or neck.

Your doctor or radiographer will tell you more about this if you need one.

You usually start planning by having a CT scan. This takes a series of pictures of the area to be treated. The CT is taken when you are in the position you need to be in for treatment. You may also have an MRI scan or a PET scan.

The scans take pictures from different angles to build up a detailed picture of the area to be treated. Using the information from the scans, your doctor looks to see where you will need treatment. A computer is used to make an individual plan for your treatment. This ensures that the radiotherapy:

• is precisely targeted at the tumour
• has a lower risk of causing side effects.

You may have to wait several weeks before the plan is ready and you can start treatment. Your treatment team will let you know how long you can expect to wait. We have more information about your radiotherapy team.

It is important that the area being treated does not move too much during your treatment. Reducing movement allows your radiographer to direct the radiotherapy more accurately. They may show you some breathing techniques, or use gentle compression on your tummy area, depending on where you are having treatment. This is done during both planning and treatment.

You may have small metal markers placed in or near your tumour. They are sometimes called fiducial markers. The markers help find the exact location of the tumour to make sure the treatment is given accurately.

The markers are about the size of a grain of rice. They are put in using a needle during a CT or ultrasound scan. The doctor gives you a local anaesthetic injection to numb the skin. They may also give you a mild sedative. This will make you feel sleepy.

The doctor then makes a small cut and puts a needle through the skin over the tumour. When the tip of the needle is in the right place, they release the marker. Usually 2 or 3 markers are needed. The markers stay in your body permanently. They are very small so you will not be aware that they are there. It is safe to have scans.

You may have markings made on your skin. These help the radiographers position you for treatment.

Usually, tiny permanent markings are made in the same way as a tattoo. The marks are the size of a pinpoint. It can be a little uncomfortable while they are being made. But it makes sure that the treatment is directed accurately. If you have a mould or radiotherapy mask, the marks may be made on this.

These marks will only be made with your permission. If you are worried about them or already have a tattoo in the treatment area, tell your radiographer. They can discuss this with you.

You may have some side effects during or after SABR. But this treatment usually causes fewer side effects than standard external beam radiotherapy. This is because the healthy tissue gets a lower dose of radiation.

Side effects do not usually happen straight away. They may develop during your course of treatment or in the days or weeks after treatment finishes. Sometimes side effects get worse for a time after you have finished radiotherapy before they get better. There may also be a small risk of side effects that are long-term. Or effects that start months or years after radiotherapy. These are called late effects. Your doctor, specialist nurse or radiographer will talk to you about any late side effects you may develop.

It is difficult to know exactly how you will react to treatment. Your team will explain what to expect. Always tell them if you have side effects during or after radiotherapy. They can give advice and support to help you cope.

The general side effects of SABR include:

• feeling tired for a few weeks after you finish treatment
• skin reactions in the treatment area, such as red, dry, itchy skin, or darkening of the skin, about 10 to 12 days after treatment
• soreness and swelling in the treatment area.

Some side effects depend on the area being treated. For example, you may have:

• chest pain
• a cough
• shortness of breath
• a raised temperature
• eating or digestion problems.