What is radiotherapy?

Radiotherapy uses high-energy x-rays to destroy cancer cells, while doing as little harm as possible to normal cells. There are two ways of having radiotherapy:

  • External-beam radiotherapy is given from outside the body (externally) by a radiotherapy machine. This is often used to treat lung cancer.
  • Internal radiotherapy (brachytherapy) is when a radioactive material is placed inside the body. Rarely this is used to treat a blocked airway.

When is external-beam radiotherapy used for SCLC?

External-beam radiotherapy for small cell lung cancer (SCLC) may be given:

  • before or after chemotherapy, if the cancer is locally advanced (sequential chemoradiation)
  • at the same time as chemotherapy, if the cancer is locally advanced (concurrent chemoradiation)
  • after chemotherapy, if the cancer has responded well to treatment
  • to the head, to stop any lung cancer cells that have spread growing into a secondary cancer in the brain (prophylactic cranial radiotherapy)
  • to control symptoms, if the cancer is more advanced or has spread to other parts of the body (palliative radiotherapy).

Having external-beam radiotherapy for SCLC

Before you start your treatment, it needs to be planned carefully by your radiotherapy team. This is to make sure the radiotherapy is aimed precisely at the cancer, causing as little damage as possible to surrounding tissue. We have more information about what to expect at your planning appointment.

You have the treatment in the hospital radiotherapy department. Usually radiotherapy is directly aimed at the lung from a radiotherapy machine. This is called external-beam radiotherapy.

You usually have a course of radiotherapy for 4 to 7 weeks. Each treatment lasts for a few minutes. You usually have treatment every day from Monday to Friday, with a rest at weekends. Your doctor or nurse will tell you how many treatments you will have.

Some people might have radiotherapy over different times or in different ways. People with SCLC sometimes have radiotherapy twice a day over three weeks. If you have radiotherapy to control symptoms, you have it over a shorter course of treatment.

Treatment sessions

At the beginning of each session of radiotherapy, the radiographer positions you carefully on the couch and makes sure you are comfortable. Radiotherapy is not painful, but you have to lie still for a few minutes during the treatment. You are alone in the room during treatment. But you can talk to the radiographer, who is watching from the next room.

Support from Macmillan

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Possible side effects of radiotherapy to the lungs

You may get some side effects over the course of your treatment. Your doctor, nurse or radiographer will talk to you about this so you know what to expect.

They will give you advice on managing side effects. Always tell them about any side effects you have. There are often things they can do to help. It can take one or two weeks after treatment before side effects start getting better. After this, most side effect usually slowly go away.


Radiotherapy often makes people feel tired. This can build up over your treatment. If you are having other treatments, such as surgery or chemotherapy, you may feel more tired.

We have more information about tiredness.

Skin changes

The skin in the treated area may get dry and irritated. Do not use perfumed soap or body wash during treatment, as it could irritate the skin. The hospital staff will advise you on how to look after your skin. If it becomes sore, your doctor can prescribe cream to help.

Difficulty swallowing

You may have:

  • difficulty swallowing
  • heartburn
  • indigestion.

This is because radiotherapy can cause inflammation in the gullet (oesophagus).

These side effects usually happen towards the end of treatment and continue for a few weeks after it finishes. Your doctor can prescribe medicines to help reduce the symptoms.

Breathlessness and a cough

You may find your breathing gets worse during radiotherapy and for a few weeks or months after it finishes. This is because radiotherapy can cause inflammation in the area of the lung being treated. It may also give you a dry cough. Always tell your doctor or nurse if:

  • you have these symptoms
  • these symptoms get worse.

Hair loss

This only happens in the treatment area. Men may lose hair on their chest, but it usually grows back. Occasionally hair loss is permanent.

Prophylactic cranial radiotherapy

If chemotherapy has worked well for SCLC, doctors sometimes recommend having radiotherapy to the brain. This is called prophylactic cranial radiotherapy (PCR).

With SCLC, there is a risk that tiny numbers of cancer cells may have spread to the brain. Over time, they would grow into secondary cancers in the brain. Your specialist may recommend PCR to stop this happening. It can help people with SCLC live longer.

We have more information about having PCR.

Palliative radiotherapy

Sometimes people have external radiotherapy to shrink the cancer and improve their symptoms. It can help them feel better so they can do more. This is called palliative radiotherapy. It is usually given when the cancer:

  • is advanced in the lung
  • has spread to other parts of the body

It may be given to improve:

  • breathlessness
  • chest pain
  • a cough
  • coughing up blood.

Some people have just one session of treatment. Other people have it over a few days. Or they might have a higher dose over one or two weeks. Your cancer doctor or nurse will explain more about this.

Doctors may use radiotherapy to treat superior vena cava obstruction. This is when the cancer is pressing on a vein in the chest and blocking the blood-flow.

People can also have palliative radiotherapy to relieve pain if the cancer has spread to areas such as the bones. They can usually have this over one or two treatments.

Internal radiotherapy

Internal radiotherapy is when treatment is given by placing radioactive material inside the body.

If the cancer is blocking one of the airways, you may have a type of internal radiotherapy (brachytherapy).

Most people have only one session of treatment. It is usually done in an operating theatre. The doctor passes a thin tube (catheter) down the nose or throat into the lung, using a bronchoscope. They put a small piece of radioactive material inside the catheter, next to the cancer. They leave it in place for a few minutes to give a dose of radiation to the cancer. Then they remove it together with the catheter.

We have more information about internal radiotherapy.

Late effects of radiotherapy for lung cancer

Late effects are side effects that:

  • you have during treatment that do not completely get better
  • develop months or years later.

Most people do not get late effects after radiotherapy to the lung. Some possible late effects are:

  • inflammation or scarring (fibrosis) in the treated area, which can cause breathlessness or a cough
  • narrowing of the gullet (oesophagus), which makes it difficult to swallow
  • a slight increase in the risk of heart problems, which might cause pain or tightness in the chest
  • thinning of the bones in the chest area, which may cause pain in that area.

If you get any of these side effects or any others, tell your cancer doctor or nurse straight away. Also let them know if any side effects you have do not improve.