adiotherapy is one of the methods of treating cancer. It uses radiation, such as X-rays, gamma rays or electrons, to either cure or control the cancer. The word comes from "radio”, meaning rays, and “therapy”, meaning treatment. It is also known as radiation treatment.  

Radiotherapy works because the radiation stops the cancer cells from growing. They are directed at the cancer in one of two ways - external radiotherapy and internal radiotherapy.  

External radiotherapy means the radiotherapy is given outside the body from a large machine that directs rays at the site of the cancer. It is rather like having an X-ray. There are a few different types of radiotherapy machines. These include:

• linear accelerators

• cobalt machines

Internal radiotherapy means the radiotherapy is given inside the body by putting a small radioactive container, fine radioactive wires or needles inside the body next to the cancer or near where the cancer is. This is called a radioactive implant. The implant contains a radioactive substance such as iridium or caesium. The implant sends rays to the cancer.  

External radiotherapy from a machine is the commonest form of radiotherapy treatment. The specialists usually use internal radiotherapy only for cancers near the surface of the body or in places that are easy to access. They can use implants for breast cancer, cancer of the cervix and cancer of the tongue. If internal radiotherapy is given then it is likely that external radiotherapy is given as well.  

The type of therapy chosen depends on the type of cancer, where it is and what size it is. Treatment has to be tailored individually. Radiotherapists only use radiotherapy if they think it will do more good than harm.  

Unfortunately, the rays cannot tell the difference between the cancer cells and the millions of normal cells in the body. However, cancer cells are not able to withstand the effects of the radiotherapy and die, whereas the normal cells recover, so there is usually no permanent damage. Because cancer cells grow faster than normal cells, they are affected more by radiotherapy. But normal cells are also affected, which is what may give the side effects.  

Some have no side effects at all. Others have a few. It depends on the region treated and the dose of radiotherapy given. Most people develop tiredness throughout their treatment course. Other side effects occur only if that particular part of the body is being treated. They include:

• feeling sick -only if the abdomen/pelvis is treated

• red, tanned or itchy skin

• sore or dry mouth or throat

• blocked ears

• losing hair or going bald -only if the head is treated

• having trouble swallowing food

• stomach ache or diarrhoea

• weak bladder

• sexual or fertility problems

Most side effects are only temporary. They will disappear soon after the treatment stops. However, some are permanent. Radiotherapy can cure some types of cancer, e.g. early cancer of the voice box, nasal area and cervix (lower part of the uterus). Sometimes, it does this when used with surgery or chemotherapy. In other cases, radiotherapy can help control cancer by stopping it growing or by shrinking it. This can give a longer life, or can help reduce some of the problems the cancer is causing or even both.

Radiotherapy has been used for many years now. There are new and better ways of giving it being found all the time. The machines are much better than they were even a few years ago. And the specialists are now able to give people much more precise amounts and be much more precise about where they direct the rays. It is now much easier to avoid harming normal cells. 

Radiotherapy does not hurt. It's just like having an X-ray. For an implant, an anaesthetic will probably be given so the patient won't feel anything. With external radiotherapy from a machine, the patient does not become radioactive. It is perfectly safe to be with and touch other people, including children and pregnant women. For those treated with implants it is not a good idea to expose other people to radioactivity meant for the patient. Once the implant is removed, the radioactivity disappears.  

It is possible that some people who have radiotherapy may later get another form of cancer. However, this is very unlikely. It is much more likely that the treatment will either cure you, or control the cancer.

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Last Updated:
Tuesday, 04 January 2005