Thousands of cancer patients to be spared radiation treatment thanks to new research
6 January 2026
Radiation treatment following surgery can be safely omitted in thyroid cancer patients whose disease is at low risk of returning, new study findings show.
The Iodine or Not (IoN) study, which ran across 33 UK cancer centres including Weston Park Cancer Centre, set out to establish whether patients with low-risk thyroid cancer could safely forego radioactive iodine treatment following surgery to remove the thyroid, a butterfly-shaped gland in the neck that produces hormones to help regulate metabolism and energy levels.
Radiation treatment targets the thyroid by using its need for iodine, allowing the radiation to destroy remaining thyroid or cancer cells while sparing healthy tissue elsewhere.
Currently, radioactive iodine is considered for most patients following surgical removal of the thyroid gland for cancer. Patients are given this treatment in hospital and must be isolated in a radiation-protected room to avoid contact with people for between one and three days.
Patients are also asked to follow safety precautions for several more days after leaving hospital. This involves avoiding or minimising contact with other people to protect them from any radiation exposure, particularly physical contact with children who are more susceptible to the low level of radioactivity the patient may have.
Thousands to be spared unnecessary treatment
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Breakthrough findings, published in the Lancet, showed that patients with low-risk thyroid cancer who did not have the therapy following thyroid cancer surgery had similar five-year cancer-free survival rates at the end of the study as those who did have surgery (98% compared to 96%). The difference in the figures was most likely down to chance rather than any clinically significant factor, the study authors said.
504 patients aged 17-80 (including over 150 aged 40 years or below) were recruited into the study. Half were randomly assigned to receive radioactive iodine treatment, which is designed to destroy any remaining cancer cells following surgery. The other half received surgery only. All patients were assessed regularly for at least five years.
Weston Park Cancer Centre, which has a particular strength in the management of endocrine cancers and radioactive iodine nationally and is home to a £4m state-of-the-art nuclear medicine and molecular radiotherapy suite, was one of the highest recruiters into the trial. The team also supported with trial management from the outset.
Global impact
Now researchers at Weston Park Cancer Centre have hailed the findings as a “breakthrough” in care, with the study findings expected to influence national and international guidelines, sparing thousands of patients the unnecessary burden of this treatment.
This is important in the treatment of thyroid cancer as unlike most cancers, it affects a high proportion of younger people who are more likely to be parents to young children. It is also three times more common in women than men.
Professor Jonathan Wadsley, Clinical Oncologist and Clinical Director for the Cancer Clinical Trials Centre at Weston Park Cancer Centre, said:
“These study findings provide high-quality evidence that a significant group of thyroid cancer patients do not benefit from radiation treatment following thyroid cancer surgery, allowing patients to avoid unnecessary treatments, reducing side effects and treatment burden on patients.
“IoN is an exemplary study, demonstrating that research does not always need to focus on new shiny treatments. By improving the delivery of existing therapies, we can make real advancements in care, stop unnecessary treatments, and enhance patients’ quality of life by reducing treatment burden, side effects, and time away from family. In addition, these advances can lead to significant savings in costs for both healthcare services and patients, lowering expenses while also freeing up clinical staff and hospital beds.”
Kate Farnell, CEO of Butterfly Thyroid Cancer Trust, said:
“On behalf of thyroid cancer patients we are delighted. Many tell us that having radioiodine treatment in isolation away from their family is perhaps the hardest part of their cancer journey. This trial has shown that in many patients this will no longer be necessary.”
Practice-changing findings
Globally, around 820,000 people are diagnosed with thyroid cancer each year, with the study authors estimating that 2,500 patients in the UK and 400,000 patients worldwide could potentially avoid radioactive iodine treatment each year.
Weston Park Cancer Centre, alongside other major UK cancer centres, has already implemented the improved treatment regime in its day-to-day management of patients who are at low risk of their thyroid cancer returning.
Other centres are also being called upon to do the same, with an expert consensus paper entitled ‘Iodine or Not for Low-risk Differentiated Thyroid Cancer: How Should We Implement the Findings into UK Practice? An Expert Consensus Opinion’ recently published in Clinical Oncology.
In Sheffield, the study was conducted with the support of the Cancer Clinical Trials Unit and Sheffield Teaching Hospitals NHS Foundation Trust's nuclear medicine team.
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