What is radiotherapy?

Radiotherapy is the use of high-energy rays to treat cancer. It is rarely used to directly treat a melanoma. Radiotherapy may be used if surgery to remove a melanoma is not possible. This may be because of other medical conditions that make surgery unsuitable. The aim is to help to control the melanoma rather than to cure it.

If you have insitu lentigo maligna and surgery is not suitable your doctor may talk to you about having radiotherapy instead. But this is not common.

Radiotherapy after surgery to remove the lymph nodes

Radiotherapy may sometimes be used after surgery to remove the lymph nodes. It is used to treat any lymph nodes or tissue that could not be removed with surgery. This may be when there is:

Radiotherapy for recurrent melanoma

Doctors sometimes use radiotherapy to treat melanoma that comes back in the same area This is called a recurrence. It may be used if the melanoma cannot be removed with surgery or other treatments are not suitable. It may help shrink large recurrences that are causing discomfort or pain. Your specialist will tell you if radiotherapy is suitable for you.

Radiotherapy for advanced melanoma

For advanced melanoma, radiotherapy may be given to reduce pain and improve other symptoms. This is called palliative radiotherapy.

Radiotherapy can help to improve symptoms when melanoma has spread to different parts of the body.

Radiotherapy to skin or lymph nodes

Radiotherapy may be used to treat melanoma that has spread to the skin or lymph nodes far from where the melanoma started. It can be used to help to shrink:

  • firm hard lumps on the skin (nodules)
  • the size of lymph nodes.

Radiotherapy will also improve symptoms, such as pain, that may be caused by swollen lymph nodes or skin nodules.

Radiotherapy to the brain

Radiotherapy can shrink melanoma that has spread to the brain. This can improve symptoms. Your doctors might suggest a radiotherapy technique called stereotactic radiosurgery (SRS). It gives a higher dose of treatment to the tumour without damaging nearby areas of the brain. This is often used instead of radiotherapy to the whole brain. You might have 1 session of SRS, or a few sessions.

Radiotherapy to the bones

Radiotherapy can help reduce bone pain and swelling. It can also be used if melanoma is in the bones of the spine and pressing on the spinal cord. This is called malignant spinal cord compression. If you have any symptoms of spinal cord compression it is very important to contact your cancer doctor straight away.

You may need only 1 to 5 sessions of treatment to treat your symptoms. Your doctor will talk to you about your treatment plan and possible side effects. Radiotherapy for melanoma does not make you radioactive. It is safe for you to be with other people after your treatment, including children.

We have more information about radiotherapy for secondary bone cancer.

How radiotherapy is given

You have the treatment in the hospital radiotherapy department. You will have a series of short, daily sessions. This is usually every day from Monday to Friday, with a rest at the weekend. Each treatment takes 10 to 15 minutes. Your doctor will talk to you about your treatment plan and the possible side effects.

If you are having stereotactic radiosurgery you may have it as a single high-dose treatment.

Planning your radiotherapy

You will have a hospital appointment to plan your treatment. You will usually have a CT 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.

Your radiotherapy team use information from this scan to plan:

  • the dose of radiotherapy
  • the area to be treated.

Treatment sessions

At the beginning of each session of radiotherapy, the radiographer will position you carefully on the couch and make sure you are comfortable. During treatment you will be alone in the room. You can talk to the radiographer, who will watch you from the next room.

We have more information about how radiotherapy is given.

Side effects of radiotherapy

Radiotherapy may cause side effects in the area of the body being treated. Your cancer doctor, nurse or radiographer will tell you what to expect. They will give you advice on what you can do to manage side effects. They may also give you medicines to help.

Usually, radiotherapy to improve symptoms causes mild side effects, especially if you only have 1 or 2 treatments.

After treatment finishes, it may be 1 to 2 weeks before side effects start getting better. After this, most side effects usually go away slowly.

You may have some general side effects, such as feeling tired. This can last for some weeks after your treatment finishes. Other side effects depend on:

  • which part of your body is being treated
  • the type of radiotherapy you have
  • how much radiotherapy you have.

We have more information about radiotherapy side effects.

Getting support

We understand that having treatment can be a difficult time for people. We're here to support you. If you want to talk, you can:

About our information

  • References

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

    Michielin O, van Akkooi ACJ, Ascierto PA, et al. Cutaneous melanoma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Annals of Oncology. 2019; 30, 12, 1884-1901 [accessed May 2022].

    Michielin O, van Akkooi ACJ, Ascierto PA, et al. ESMO consensus conference recommendations on the management of locoregional melanoma: under the auspices of the ESMO Guidelines Committee. Annals of Oncology. 2020; 31, 11, 1449-1461 [accessed May 2022].

    Peach H, Board R, Cook M, et al. Current role of sentinel lymph node biopsy in the management of cutaneous melanoma: A UK consensus statement. Journal of Plastic, Reconstructive & Aesthetic Surgery. 2020; 73, 1, 36-42 [accessed May 2022].

  • 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 Samra Turajlic, Consultant Medical 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.

The language we use

We want everyone affected by cancer to feel our information is written for them.

We want our information to be as clear as possible. To do this, we try to:

  • use plain English
  • explain medical words
  • use short sentences
  • use illustrations to explain text
  • structure the information clearly
  • make sure important points are clear.

We use gender-inclusive language and talk to our readers as ‘you’ so that everyone feels included. Where clinically necessary we use the terms ‘men’ and ‘women’ or ‘male’ and ‘female’. For example, we do so when talking about parts of the body or mentioning statistics or research about who is affected.

You can read more about how we produce our information here.

Date reviewed

Reviewed: 01 October 2022
Next review: 01 October 2025
Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

This means it is easy to use, up-to-date and based on the latest evidence. Learn more about how we produce our information.