What is radiotherapy?

Radiotherapy uses high-energy x-rays to destroy cancer cells, while doing as little harm as possible to normal cells. It can be used in different situations, depending on the type and stage of lung cancer you have.

Having external beam radiotherapy

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 planned. Each treatment lasts for a few minutes. Your doctor or nurse will tell you how many treatments you will have.

You may have radiotherapy over different times and in different ways. Some people have it once a day Monday to Friday, with a break at the weekend. This may be done over 4 to 7 weeks.

You may have it more than once a day and over the weekend (hyper-fractionated). Sometimes specialist radiotherapy techniques are used.

To control symptoms, radiotherapy may be given over a shorter time, often 5 to 10 days.

Planning your radiotherapy treatment

You will have a hospital appointment to plan your treatment. You will usually have a CT planning scan of the area to be treated. During the scan, you need to lie in the position that you will be in for your radiotherapy treatment.

You may need to have some small, permanent markings made on your skin. The marks are about the size of a pinpoint. They help the radiographer make sure you are in the correct position for each session of radiotherapy.

These marks will only be made with your permission. If you are worried about them, talk to your radiographer.

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.

Radiotherapy for non-small cell lung cancer (NSCLC)

Radiotherapy for non-small cell lung cancer (NSCLC) may be given:

  • on its own instead of surgery, to try to cure early-stage NSCLC
  • after surgery, to reduce the risk of cancer coming back (adjuvant radiotherapy)
  • at the same time as chemotherapy , if the cancer is locally advanced (concurrent chemoradiotherapy)
  • before or after chemotherapy, if the cancer is locally advanced (sequential chemoradiation )
  • to control symptoms, if lung cancer has spread to other parts of the body (palliative radiotherapy).

Stereotactic ablative radiotherapy (SABR) for NSCLC

(SABR) is a specialised type of radiotherapy. It may be used to try to cure a small tumour that has not spread to the lymph nodes in the chest. This is usually when you cannot have, or do not want, surgery. SABR is not available at every hospital, so you may have to travel to have it.

Your cancer team use scans, specialist machinery and complex planning to target the radiotherapy beams very precisely. This gives a very high dose of radiotherapy to small cancers, and only a low dose to healthy tissue surrounding it. This helps to reduce side effects.

People usually have SABR as 3, 5 or 8 treatments on every other day.

Radiotherapy for small cell lung cancer (SCLC )

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 chemoradiotherapy)
  • after chemotherapy, if the cancer has responded to treatment
  • to control symptoms, if the cancer is more advanced or has spread to other parts of the body (palliative radiotherapy)
  • to the head to stop any lung cancer cells that may have spread, forming a secondary cancer in the brain (prophylactic cranial radiotherapy).

CHART for non-small cell lung cancer

CHART stands for continuous hyper-fractionated accelerated radiotherapy. You have radiotherapy 3 times a day including weekends, for 12 days. Each treatment must be at least 6 hours apart. You usually have to stay in the hospital or somewhere nearby during treatment.

Your doctor can tell you if CHART is suitable for you. It is not available at every hospital, so you may have to travel to have it.

Preventive radiotherapy to the brain for SCLC

If chemotherapy has been helpful, your cancer doctor may talk to you about having radiotherapy to the brain. This is called prophylactic cranial radiotherapy (PCR).

With SCLC, there is a risk that tiny numbers of cancer cells too small to see on a scan may have spread to the brain. Over time this could develop into a secondary cancer in the brain. PCR can reduce this risk and help people with SCLC to live longer. Your doctor and nurse will explain what is involved and what the side effects are before you decide.

Palliative radiotherapy for lung cancer

Sometimes people have external radiotherapy to shrink the cancer and improve their symptoms. This is called palliative radiotherapy.

It may be given to improve:

Some people have just one session of treatment. Other people have it over a few days. Or they might have a higher dose over 1 or 2 weeks. Your cancer doctor or nurse will explain more about this.

Internal radiotherapy

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. 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.

Superior vena cava obstruction

Doctors may use radiotherapy to treat a condition called superior vena cava obstruction. This is when the cancer is pressing on a large vein in the chest causing a blockage to the blood-flow.

Spinal cord compression

Radiotherapy may also be used if lung cancer that has spread to the spine or near it and is causing pressure on the spinal cord. This is called spinal cord compression (SCC).

Side effects of radiotherapy for lung cancer

You may get some side effects over the course of your treatment. Your doctor, nurse or radiographer will explain the side effects so you know what to expect. Tell them about any side effects you have. There are often things they can do to help. They will also give you advice on how you can manage side effects.

It can take 1 or 2 weeks after treatment before side effects start getting better. After this, most side effect usually slowly go away.

We have more information about the side effects of radiotherapy.

Difficulty swallowing

You may have:

  • difficulty swallowing
  • pain or discomfort when you swallow
  • heartburn
  • indigestion.

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

Your doctor can prescribe medicines to help reduce the symptoms.

If you have difficulty eating, you can replace meals with nutritious, high-calorie drinks.


Tiredness can build up over your treatment. If you are having other treatments, you may feel more tired. Try to pace yourself and get plenty of rest.

Sometimes tiredness can continue for weeks or months after treatment finishes. If it does not get better, tell your doctor or nurse.

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.

They may prescribe steroids to help improve your symptoms.

Skin changes

The skin in the treated area may get dry and irritated. The hospital staff will advise you on how to look after your skin. If it becomes sore, your doctor can prescribe cream to help.

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.

Late effects of radiotherapy for lung cancer

Late effects are side effects that do not go away or side effect that develop months or years after treatment.

Some possible late effects are:

  • inflammation or scarring (fibrosis) in the treated area of the lung, 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. There are different things that can be done to manage late effects. Also let them know if any side effects do not improve.

About our information

  • References

    Below is a sample of the sources used in our lung cancer information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk

    National Institute for Health and Care Excellence (NICE). Lung cancer – Diagnosis and management. Clinical guideline 2019.

    Metastatic non-small cell lung cancer: ESMO clinical practice guidelines for diagnosis, treatment and follow-up. 2018.

    European Society for Medical Oncology (ESMO). Early and locally advanced non-small-cell lung cancer (NSCLC): ESMO clinical practice guidelines for diagnosis, treatment and follow-up. 2017. European Society for Medical Oncology (ESMO).

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editor, Dr David Gilligan, Consultant Clinical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

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