External beam radiation therapy (also known as external beam radiotherapy) uses a controlled dose of radiation to kill cancer cells or damage them so they cannot grow, multiply or spread. The radiation is usually in the form of x-ray beams. Radiation is delivered precisely to the affected area, which reduces treatment time and side effects.
Learn more about:
- When is external radiation therapy used?
- Planning session
- Having treatment
- Side effects of external radiation therapy
- Video: What is radiation therapy?
When is external beam radiation therapy used?
Most people diagnosed with thyroid cancer do not need external beam radiation therapy, but it may be recommended in particular circumstances. In a small number of cases, it may be given:
- after surgery and RAI treatment if the cancer has not been completely removed or if there is a high risk of the cancer returning (recurrence)
- as palliative treatment to relieve symptoms such as pain caused by cancer that has spread to nearby tissue or structures
- to help control medullary or anaplastic thyroid cancer (because these types do not respond to RAI).
Planning session
Before the treatment starts, you will have a planning session. The radiation therapist will take CT scans to work out the exact area to be treated, and may make small marks or tattoos on your skin. This ensures the same part of your body is targeted during each treatment session.
You may also be fitted for a plastic mask to wear during treatment. This will help you stay still so that the radiation is targeted at the same area of your neck during each session. You can see and breathe through the mask, but it may feel strange and uncomfortable at first. The radiation therapy team can help you manage this.
Having treatment
Radiation therapy is usually given five days a week over several weeks. Treatment sessions usually take about 10 minutes, but it will take longer to position the machine correctly.
Side effects of external beam radiation therapy
Many people develop side effects during radiation therapy. Common side effects include feeling tired, difficulty swallowing, sore throat, dry mouth, and red, dry, itchy, sore or ulcerated skin. Most of these will disappear within a few weeks or months. Your treatment team can help you prevent or manage any side effects.
Video: What is radiation therapy?
Watch this short video to learn more about radiation therapy.
Key resource
Download a PDF booklet on this topic.
More resources
A/Prof Diana Learoyd, Endocrinologist, Northern Cancer Institute, and Northern Clinical School, The University of Sydney, NSW; Dr Gabrielle Cehic, Nuclear Medicine Physician and Oncologist, South Australia Medical Imaging (SAMI), and Senior Staff Specialist, The Queen Elizabeth Hospital, SA; Dr Kiernan Hughes, Endocrinologist, Northern Endocrine and St Vincents Hospital, NSW; Yvonne King, 13 11 20 Consultant, Cancer Council NSW; Dr Christine Lai, Senior Consultant Surgeon, Breast and Endocrine Surgical Unit, The Queen Elizabeth Hospital, and Senior Lecturer, Discipline of Surgery, University of Adelaide, SA; A/Prof Nat Lenzo, Nuclear Physician and Specialist in Internal Medicine, Group Clinical Director, GenesisCare Theranostics, and The University of Western Australia, WA; Ilona Lillington, Clinical Nurse Consultant (Thyroid and Brachytherapy), Cancer Care Services, Royal Brisbane Women’s Hospital, QLD; Jonathan Park, Consumer.
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