External Beam Radiotherapy for Thyroid Cancer
External beam radiotherapy uses focused radiation to treat cancer. In thyroid cancer it is used selectively — for advanced disease that cannot be fully removed, for recurrence, or to relieve symptoms such as pain or compression.
It is not a routine treatment for most thyroid cancers, which are usually managed with surgery and radioactive iodine.
Last medically reviewed: 15 November 2025
Key points
- External beam radiotherapy is used for selected advanced or recurrent thyroid cancer.
- It is not routine for early thyroid cancer.
- Treatment is delivered in short daily sessions over several weeks.
- It can relieve pain and compression from advanced disease.
When it is used
Radiotherapy may be considered when thyroid cancer invades surrounding structures, when surgery cannot remove all disease, or when there is recurrence in the neck that is not suitable for further surgery or radioactive iodine.
It is also used for palliation of pain or compression in advanced disease, including anaplastic thyroid cancer.
How treatment is given
A planning scan maps the area to be treated, and the radiation dose is carefully shaped to target the tumour while sparing nearby structures. Treatment is usually given in short daily sessions over several weeks.
Each session is painless and lasts only a few minutes.
Side effects
Short-term effects can include skin redness, tiredness, sore throat and difficulty swallowing. Longer-term effects may include dry mouth, neck stiffness or thyroid hormone changes.
The team monitors and manages side effects throughout treatment.
Coordinated care
Radiotherapy is planned by a multidisciplinary team including radiation oncology, surgery and endocrinology. It is often combined with other treatments rather than used alone.
When to seek urgent medical help
- Severe difficulty breathing or swallowing during treatment.
- Rapidly increasing neck swelling.
- Fever or severe skin reactions during radiotherapy.
This guidance does not replace emergency services. If you are seriously unwell, seek urgent medical care immediately.
Frequently asked questions
Will I need radiotherapy for thyroid cancer?
Most people do not. It is used selectively for advanced, recurrent or symptomatic disease.
Is radiotherapy painful?
The treatment itself is painless. Side effects such as skin irritation or sore throat can occur.
Can it cure thyroid cancer?
It can control local disease and relieve symptoms, but it is usually part of combined treatment rather than a standalone cure.
How long does treatment take?
Usually several weeks of short daily sessions, depending on the dose and area treated.
References & further reading
This page is based on established medical knowledge and guidelines from authoritative sources. Always consult a qualified clinician for personal medical advice.
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