Radiotherapy

What is radiotherapy?

Radiotherapy is a treatment for cancer. High energy beams of radiation are focussed on cancerous tissue. This kills cancer cells, or stops cancer cells from multiplying. Radiotherapy is sometimes called radiation therapy.

What are the aims of radiotherapy?

Radiotherapy and other treatments may aim to cure the cancer
A cure is the aim in many cases. Some cancers can be cured with radiotherapy alone. Sometimes radiotherapy is used in addition to another main treatment. For example:

• You may have surgery to remove a tumour but you may also be given a course of radiotherapy after the surgery. This aims to kill any cancer cells which may have remained following surgery. Unless treated, these may have caused a recurrence of the tumour at a later time. Radiotherapy given after surgery is called adjuvant radiotherapy.
• Sometimes radiotherapy is given before surgery to reduce the size of the tumour and make it easier to remove. Radiotherapy given before surgery is called neoadjuvant radiotherapy.
• In some cases radiotherapy and chemotherapy are used in combination. (See separate leaflet about chemotherapy.)

Doctors tend to use the word 'remission' rather than the word 'cured'. Remission means there is no evidence of cancer following treatment. If you are 'in remission', you may be cured. However, in some cases a cancer returns months or years later. This is why some doctors are reluctant to use the word cured.

Radiotherapy and other treatments may aim to control the cancer
If a cure is not realistic, with treatment it is often possible limit the growth or spread of the cancer so that it progresses less rapidly. This may keep you free of symptoms for some time.

Radiotherapy may be used to ease symptoms
Even if a cure is not possible and the outlook is poor, a course of radiotherapy may be used to reduce the size of a cancer. This may ease symptoms such as pain or pressure symptoms from the tumour. This is called 'palliative' radiotherapy.

How is radiotherapy given?

There are two main types of radiotherapy:

• External radiotherapy where the radiation comes from a machine from outside the body.
• Internal radiotherapy where the radiation comes from implants or liquids placed inside the body.

External radiotherapy

External radiotherapy is the most common type of radiotherapy. A machine is used which emits radiation - usually high intensity x-rays, but other types of radiation are sometimes used.

Planning a course of treatment
A course of treatment is planned by a specialist and is based on the type, size and location of your cancer. The total dose of radiation needed to treat the cancer is carefully calculated. The total dose is then divided into many 'fractions'. Usually the plan is then to have a short session of radiotherapy treatment on most days each week, for several weeks. You receive a 'fraction' of the total dose of radiation at each separate treatment session. Treatment sessions continue until you have had the total dose or radiation. By having a small fraction of the total dose on many sessions, it is more likely to work better than having the whole dose at one session, and reduces the severity of side-effects.

During each treatment session, the aim is to get as much of the radiation as possible to focus on cancerous cells, with as little radiation as possible to affect normal cells. Before the first session, your specialist will carefully plan the exact direction and approach of the radiation from the machine, and the exact position you need to lie for each session of treatment. This will often involve tests such as CT scans, X-rays, etc, to find the exact site of the cancer in your body.

The specialist may mark a site on your skin with permanent ink. This is the 'target' and ensures that during each treatment session the radiation is aimed at the same spot. Sometimes a more permanent tiny tattoo is used for the same purpose. Sometimes a special cast is made which is put over the area to be treated during each treatment session. A mark is placed on the cast (instead of on the skin) as the target for the radiation machine to aim at. A cast is particularly useful for treatment of certain cancers of the head and neck. The cast keeps the head perfectly still and in the same position for each treatment session.

What happens during treatment sessions?
You may be asked to put on a hospital gown for each treatment session. The treatment is given in a special radiotherapy room. You will usually lie on a couch and the radiation machine is positioned above you. The therapist may adjust your position, and adjust the angle and position of the machine so that when it emits radiation the rays are focussed at exactly the right part in your body (through the mark on your skin or cast). Lead shields may be placed over certain areas of your body to protect them from the radiation.

When you are settled, the therapist has to go out into a separate control room (for their own protection from repeated exposure to radiation). In the control room they can see you via a TV monitor or through a window, and you will still be able to talk to them. The therapist then uses controls to emit radiation from the machine for a short time.

Each session of treatment usually only lasts a few minutes (although it may take several minutes to position you and the machine correctly each time). During each treatment session the radiation may be emitted several times in short bursts from different angles. So, you or the machine may need to be adjusted a few times during a treatment session. One reason why this may be done is that although each burst of radiation will focus on the cancer, each burst will pass through different parts of your body on the way. This aims to reduce damage to normal tissues.

Is external radiotherapy painful?
No. It is similar to having an X-ray. You do not feel the radiation, and it is not 'hot'. If side-effects occur, they develop at a later time.

Internal radiotherapy

Internal implants
This involves inserting a small radioactive implant into the cancerous tumour, or next to the tumour. The implants come in different shapes and sizes (small rods, pellets, etc), and can contain different radioactive materials. An anaesthetic may be needed to allow the doctor to place the implant in the correct place. Radioactive implants are used mainly for some cancers of the uterus, vagina, rectum, cervix, prostate, mouth and neck.

Some types of implant are removed after a few days. Some types are only left in place for a few minutes. Some types are left in place long-term. For example, radioactive 'seeds' are sometimes placed into prostate tumours and are left indefinitely.

Radioactive liquids
In some situations a liquid can contain a radioactive substance. For example, one treatment for thyroid cancer is to take a drink which contains radioactive iodine. The radioactive iodine is absorbed into the bloodstream and taken up by thyroid cells (both normal and cancerous). So, the radioactive iodine concentrates and builds up in thyroid cells. This then destroys the thyroid cells, but has little effect on any other tissue in the body.

Does radiotherapy make me 'radioactive'?

External radiotherapy does not make you radioactive. The radiation comes from the machine and does not 'stay' in you.

For internal radiotherapy, whilst a radioactive implant is in place you will be emitting a certain amount of radioactivity. This is why there may be restrictions on your movements and visitors whilst certain types of implant are in place. However, most of the radioactivity is concentrated around the tumour being treated. Once the implant is removed, you no longer emit radioactivity.

What are the possible side-effects of radiotherapy?

Radiotherapy aims to kill or damage cancer cells, but inevitably some normal cells will be damaged which can lead to side-effects. Normal cells are usually able to recover better than cancer cells and side-effects are often temporary (although some are permanent). Also, even with the same treatment schedule, different people can react differently and some people develop more severe side-effects than others.

Possible side-effects depend on the area of the body being treated. For example: radiotherapy to a tumour in the the head and neck may cause a sore mouth; radiotherapy to the pelvis may cause fertility or sexual problems. It is beyond the scope of this leaflet to discuss all the possible side-effects which may occur from radiotherapy to every part of the body.

Your specialist will normally discuss with you the possible side-effects that may occur following radiotherapy to the particular area of your body being treated.

Further help and information

CancerBACUP, 3 Bath Place, Rivington Street, London, EC2A 3JR
Tel: 0808 800 1234    Web: www.cancerbacup.org.uk
Provides information and support to anyone affected by cancer.

Cancer Research UK
Their website www.cancerhelp.org.uk provides facts about cancer including treatment choices.

Other support groups
A list of the many self help and support groups for cancer patients, their families, carers and friends can be found at: www.patient.co.uk

© EMIS and PIP 2004   Updated: May 2004   Review Date: June 2005   CHIQ Accredited