What is radiotherapy?

Radiotherapy helps to cure just under half of all patients who are cured of their cancer. It’s a treatment that involves radiation produced in an X-ray machine, which can be neither seen nor felt. It’s painless but is able to damage cancer cells. It also damages normal cells, but they recover from the injury much better, whereas the cancer cells die. It has a high success rate.

Radiotherapy is largely used to treat and control many different types of cancer. It can shrink a cancerous tumour (abnormal cell growth) before it is surgically removed. The aim of radiotherapy is to kill the cancerous cells in the affected area of the body. However, there are some benign conditions that can be treated, such as thyroid disease or bone formation around a hip replacement

Radiotherapy is used as a local treatment, either by itself or sometimes with surgery. Many women with early breast cancer can have the lump removed and then have radiotherapy to treat the surrounding area. Radiotherapy can also be used in combination with chemotherapy. Patients may have a course of chemotherapy and, when the cancer has shrunk, there will be local treatment with radiotherapy to make sure the patient is cured.

Long-term risks vary from person to person, so you need to have a detailed conversation with your consultant about the hazards. Radiotherapy itself does not hurt. You can hear the machine but you do not feel anything at the time. It can produce side effects. Patients can feel sick afterwards, so they will be given anti-sickness drugs.

Depending on what part of the body is being treated, there can be other side effects, such as sore skin or diarrhoea. Those side effects would be discussed with you by your consultant before treatment. An important risk for all patients is that radiotherapy may induce a second cancer. This is rare, but it’s an important complication that doctors should discuss with every patient.

Radiotherapy can be given externally or internally. External radiotherapy usually involves a course of treatment over days or weeks. Internal radiotherapy is usually given once or a small number of times.

External radiotherapy

External radiotherapy is given outside the body. A machine focuses high-energy X-rays, cobalt irradiation or other high-energy beams at the cancer. Surrounding healthy cells are also affected but are able to repair themselves following treatment. If radiotherapy is recommended for you, you will be referred to a specialist radiotherapy department where you will receive your treatment. The type of machine used will depend on the reason for your treatment and the condition that you are being treated for, for example the type of cancer you have.

You will not feel any pain during the treatment, but you may later experience some pain or discomfort from the side effects of the treatment. Most side effects can be controlled and do not usually last long.

Other types of external radiotherapy

As well as standard external radiotherapy, using X-rays or other high-energy sources, there are a number of other types of external radiotherapy.

Conformal radiotherapy

Conformal radiotherapy uses the same type of machine as standard external radiotherapy. However, metal blocks are put in front of the radiation beam, changing the shape of the beam so that it conforms closely to the shape of the tumour. This enables a higher dose of radiation to be used, increasing the chance of killing the cancerous cells. There is also a lower chance of long-term side effects because healthy tissue is affected less.

Intensity modulated radiotherapy

In intensity modulated radiotherapy (IMRT), computers control the radiotherapy machine. This allows very precise doses of radiation to be given to specific areas of the tumour. Before the procedure, a three-dimensional scan is taken to match the intensity of the dose with the shape of the tumour. In IMRT, the cancerous tumour receives a very high dose of radiation while the surrounding healthy tissue receives a very low dose. As with conformal radiotherapy, side effects following treatment are likely to be lower than with standard external radiotherapy.

Internal radiotherapy

Internal radiotherapy uses radioactive materials (metals or liquids) to treat cancer. The two main types of internal radiotherapy are radioactive implants, and radioactive liquids.

Radioactive implants

Radioactive implants are usually metal wires, seeds or tubes. They are inserted close to the cancerous tumour in a procedure known as brachytherapy. How long the radioactive implant is left inside your body depends on the type and nature of your cancer and could be a few minutes or a few days. In some cases, radioactive implants may be left inside the body permanently.

Caesium and iridium are radioactive metals that are sometimes used to treat cancer of the cervix, womb and vagina.

Radioactive liquids

Radioactive liquids to treat cancer are given either as a drink or an injection. The radioactive part of the liquid is known as an isotope. Radioactive liquids include:

• phosphorous, used to treat blood disorders,
• strontium, used to treat secondary bone cancers, and
• iodine, used to treat benign (non-malignant) thyroid conditions and thyroid cancer.

Safety

Health risks associated with radiotherapy are generally low because the amount of radiation used is usually very small. However, as internal radiotherapy involves placing radioactive substances inside your body, there are some safety issues you will need to discuss with your treatment team.

If you have a radioactive implant or radioactive liquid, your hospital will have a number of safety guidelines to ensure that hospital staff and visitors are not exposed to radiation. The hospital staff will explain the safety procedures to you before treatment.

Radioactive implants are inserted next to the cancerous tumour so that it gets the highest dose of radiation. The area that is close to the implant will also get a high dose of radiation. Other parts of your body will receive a very small amount of radiation, which isn’t a risk to your health. Your body will give out a low level of radiation for a few days after having radioactive liquid. This gradually decreases as the radioactivity breaks down.

If you receive your radiotherapy treatment as an inpatient (you stay in hospital overnight), your treatment team can give you advice about visitors while you are in hospital and will ensure the radiation has decreased to a safe level before you are discharged.

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