Differentiated Thyroid CancerIULIDNCT05599139
Iodine Uptake After a Low Iodine Diet
A study testing Low iodine diet in people with Differentiated Thyroid Cancer, run by University Medical Center Groningen at 1 site in Netherlands.
Trial summary
The goal of this clinical trial is to compare the difference in thyroid uptake of a low dose radioactive iodine (10 MBq 123-I or 37 MBq 123-I) in athyreotic patients with differentiated thyroid carcinoma before and after a low iodine diet (LID) of 7 days. Read more about this study
- Who is it for?
- Ages 18 to 75 years
- Conditions the study is for
- Differentiated Thyroid Cancer
- What is being tested?
- Low iodine diet
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 25 participants
- Where
- 1 siteNetherlands
- Study dates
- 22 Feb 2023to 31 Aug 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 75 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Patients, men and women above the age of 18 years, have to be diagnosed with DTC and have to follow a LID prior to the 131I ablation therapy according to the Dutch DTC guideline
- Patients have to be fit to adhere to the study protocol
- Patients have to be able to read and understand the Dutch language
Who cannot join
- Age < 18 years
- Patients using amiodarone
- Patients receiving iodinated contrast < 3 months before the LID
- Pregnancy
- Patients prepared for ablation therapy with rhTSH
- Renal impairment, EGFR <30ml/min/1,73m2
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Netherlands1 site, 1 recruiting
- Recruiting
UMCG
Groningen, Provincie Groningen, 9713GZ
Wouter T Zandee, MD PhD, 050 361 6161, w.t.zandee@umcg.nl
Mirthe H Links, Bsc, 050 361 6161, m.h.links@umcg.nl
About this study
Official title: The Uptake of Radioactive Iodine Before and After a Low Iodine Diet in Patients With Differentiated Thyroid Carcinoma
The goal of this clinical trial is to compare the difference in thyroid uptake of a low dose radioactive iodine (10 MBq 123-I or 37 MBq 123-I) in athyreotic patients with differentiated thyroid carcinoma before and after a low iodine diet (LID) of 7 days.
The main question it aims to answer is:
- What is the difference in iodine uptake before and after a LID of 7 days?
Uptake of a low dose of 123-iodine will be measured in participants before and after a low iodine diet of 7 days. Researchers will compare the uptake (%) before and after the LID.
Read the detailed description
Rationale:
Differentiated thyroid carcinoma (DTC) is the most common form of thyroid cancer. The initial treatment of DTC consists of a total thyroidectomy followed by ablation therapy with radioactive iodine (131I) which destroy residual thyroid (cancer) tissue. Before starting the (ablation) therapy with 131I, patients have to follow a low iodine diet (LID) reducing the iodine intake < 50 mcg per day. Depleting the overall iodine store in the body theoretically maximizes the expression of the sodium-iodine symporter (NIS). This increased NIS expression results in an increase of the uptake of 131I in remaining thyroid (cancer) cells during 131I therapy and therefore improves the ablation success rates. However, there is no prospective data to support this, merely some retrospective contradictionary data. Patients experience the strict adherence to LID as stressful, distasteful and overwhelming in combination with a new diagnosis of cancer and withdrawal from thyroid hormone. Besides, they are afraid to apply the LID inadequately, which complicates achieving a balanced diet, essential in cancer recovery.
Objective:
To compare the difference in thyroid uptake of a low dose radioactive iodine (10 MBq 123I or 37 MBq 123I), in DTC patients after thyroidectomy, before and after a LID of 7 days.
Study design: observational, single center study performed in the University Medical Center Groningen (UMCG) Groningen, the Netherlands.
Study population: Patients, men and women above the age of 18 years, with a histopathological confirmed diagnosis of DTC who will receive 131I ablation therapy and have to follow a LID according to the Dutch DTC guideline.
Main study parameters/endpoints: The primary endpoint is the clinical relevant difference of a twofold uptake increase, in the thyroid remnant after thyroidectomy in DTC patients, a 10 MBq 123I or 37 MBq 123I tracer dose before and after a LID of 7 days.
Nature and extent of the burden and risks associated with participation, benefit and group relatedness:
- Burden: Low risk patients (according to the Dutch DTC guideline) will receive 10 MBq 123I twice, followed by a thyroid uptake measurement and will have to collect their urine for 24 hours twice. High risk patients (according to the Dutch DTC guideline) will receive 10 MBq 123I once, followed by a thyroid uptake measurement and have to collect their urine for 24 hours twice. On the day of the first administration of 10 MBq 123I, 1 blood sample (5 ml) will be collected. Low risk patients have to make three additional site visits to the UMCG, high risk patients two additional site visits.
- Risks: The administration of two times 10 MBq will lead to an extra radiation exposure of 0,76 mSv for low risk patients and 0,38 mSv for high risk patients. Blood sampling carriers a negligible risk of a hematoma. The 24 hours urine collection is without additional risk for the patient or the lab technician.
The note of the daily food intake is without additional risk for the patient.
- Benefits: None, participants will participate based on altruistic motives.
- Conditions
- Differentiated Thyroid Cancer
- Being tested
- Low iodine diet
- Keywords
- Low iodine diet, Iodine uptake
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Low iodine dietBehavioural
Before ablation and possible subsequent therapy with 131I, patients have to follow a low iodine diet (LID), reducing the iodine intake < 50 mcg per day and thereby depleting the overall iodine store in the body.
| Study group | Role | What they receive |
|---|---|---|
| Low iodine diet | Other | Patients recieve a low iodine diet. Consecutive iodine uptake measurements will be made before and after starting this low iodine diet. This study is constructed of only one study arm, and patients will be compared to themselves. Receives: Behavioral: Low iodine diet |
What is being measured
The primary outcome is the main question the study is designed to answer.
Iodine uptake
Difference in iodine uptake in percentage
Measured: 7 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted31 Oct 2022
- Study start22 Feb 2023
- Primary completion30 Mar 2026 (estimated)
- Study completion31 Aug 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Differentiated Thyroid CancerStudies of the same condition, open and under way.
- More trials run by University Medical Center GroningenThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 25 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University Medical Center Groningen
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Wouter Zandee, Dr., Principal investigator, University Medical Center Groningen
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05599139
- Sponsor's protocol ID
- NL65923.042.18
- Acronym
- IULID
- Status last verified
- Feb 2026
- First submitted
- 25 Oct 2022
- Last updated
- 6 Feb 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: The IPD will not be available to other researchers as this is not included in the patient consent.
Study at a glance
From the registry record, last updated by the sponsor on 6 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Uptake of Radioactive Iodine Before and After a Low Iodine Diet in Patients With Differentiated Thyroid Carcinoma
- ClinicalTrials.gov ID
- NCT05599139
- Acronym / sponsor ID
- IULID / NL65923.042.18
- Conditions
- Differentiated Thyroid Cancer
- Keywords
- Low iodine diet, Iodine uptake
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 25 participants (estimated)
- Lead sponsor
- University Medical Center GroningenUniversity, hospital or other
- Study start
- 22 Feb 2023 (actual)
- Primary completion
- 30 Mar 2026 (estimated)
- Study completion
- 31 Aug 2026 (estimated)
- First posted
- 31 Oct 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this clinical trial is to compare the difference in thyroid uptake of a low dose radioactive iodine (10 MBq 123-I or 37 MBq 123-I) in athyreotic patients with differentiated thyroid carcinoma before and after a low iodine diet (LID) of 7 days.
The main question it aims to answer is:
- What is the difference in iodine uptake before and after a LID of 7 days?
Uptake of a low dose of 123-iodine will be measured in participants before and after a low iodine diet of 7 days. Researchers will compare the uptake (%) before and after the LID.
Detailed description
Rationale:
Differentiated thyroid carcinoma (DTC) is the most common form of thyroid cancer. The initial treatment of DTC consists of a total thyroidectomy followed by ablation therapy with radioactive iodine (131I) which destroy residual thyroid (cancer) tissue. Before starting the (ablation) therapy with 131I, patients have to follow a low iodine diet (LID) reducing the iodine intake < 50 mcg per day. Depleting the overall iodine store in the body theoretically maximizes the expression of the sodium-iodine symporter (NIS). This increased NIS expression results in an increase of the uptake of 131I in remaining thyroid (cancer) cells during 131I therapy and therefore improves the ablation success rates. However, there is no prospective data to support this, merely some retrospective contradictionary data. Patients experience the strict adherence to LID as stressful, distasteful and overwhelming in combination with a new diagnosis of cancer and withdrawal from thyroid hormone. Besides, they are afraid to apply the LID inadequately, which complicates achieving a balanced diet, essential in cancer recovery.
Objective:
To compare the difference in thyroid uptake of a low dose radioactive iodine (10 MBq 123I or 37 MBq 123I), in DTC patients after thyroidectomy, before and after a LID of 7 days.
Study design: observational, single center study performed in the University Medical Center Groningen (UMCG) Groningen, the Netherlands.
Study population: Patients, men and women above the age of 18 years, with a histopathological confirmed diagnosis of DTC who will receive 131I ablation therapy and have to follow a LID according to the Dutch DTC guideline.
Main study parameters/endpoints: The primary endpoint is the clinical relevant difference of a twofold uptake increase, in the thyroid remnant after thyroidectomy in DTC patients, a 10 MBq 123I or 37 MBq 123I tracer dose before and after a LID of 7 days.
Nature and extent of the burden and risks associated with participation, benefit and group relatedness:
- Burden: Low risk patients (according to the Dutch DTC guideline) will receive 10 MBq 123I twice, followed by a thyroid uptake measurement and will have to collect their urine for 24 hours twice. High risk patients (according to the Dutch DTC guideline) will receive 10 MBq 123I once, followed by a thyroid uptake measurement and have to collect their urine for 24 hours twice. On the day of the first administration of 10 MBq 123I, 1 blood sample (5 ml) will be collected. Low risk patients have to make three additional site visits to the UMCG, high risk patients two additional site visits.
- Risks: The administration of two times 10 MBq will lead to an extra radiation exposure of 0,76 mSv for low risk patients and 0,38 mSv for high risk patients. Blood sampling carriers a negligible risk of a hematoma. The 24 hours urine collection is without additional risk for the patient or the lab technician.
The note of the daily food intake is without additional risk for the patient.
- Benefits: None, participants will participate based on altruistic motives.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Low iodine diet | Other | Behavioral: Low iodine dietPatients recieve a low iodine diet. Consecutive iodine uptake measurements will be made before and after starting this low iodine diet. This study is constructed of only one study arm, and patients will be compared to themselves. |
Who may qualify
- Ages
- 18 to 75 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Patients, men and women above the age of 18 years, have to be diagnosed with DTC and have to follow a LID prior to the 131I ablation therapy according to the Dutch DTC guideline
- Patients have to be fit to adhere to the study protocol
- Patients have to be able to read and understand the Dutch language
Key exclusion criteria (6 listed)
- Age < 18 years
- Patients using amiodarone
- Patients receiving iodinated contrast < 3 months before the LID
- Pregnancy
- Patients prepared for ablation therapy with rhTSH
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Low iodine dietBefore ablation and possible subsequent therapy with 131I, patients have to follow a low iodine diet (LID), reducing the iodine intake < 50 mcg per day and thereby depleting the overall iodine store in the body. | Behavioural | Low iodine diet |
Primary outcome
Iodine uptake
Time frame: 7 days
Difference in iodine uptake in percentage
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Feb 2026.
- Individual participant dataSharing planned: No. The IPD will not be available to other researchers as this is not included in the patient consent.
Related trials for Differentiated Thyroid Cancer
RecruitingPhase 2
Study of ST-1898 in Locally Advanced or Metastatic Radioiodine-Refractory Differentiated Thyroid Cancer
Differentiated Thyroid Carcinoma
Not yet recruitingObservational study
Serum Treg/Th17-Related Cytokines and Systemic Inflammatory Indices in Differentiated Thyroid Cancer
Differentiated Thyroid Cancer (DTC), Papillary Thyroid Carcinoma
RecruitingPhase 2
The Use of 124-I-PET/CT Whole Body and Lesional Dosimetry in Differentiated Thyroid Cancer
Thyroid Cancer
Enrolling by invitationPhase 3
Long-Term Extension Study for Participants Previously Enrolled in an Exelixis-Sponsored Study
Cancer, Renal Cell Carcinoma (RCC)
Not yet recruitingPhase 1
Study of ACC-1898 in Adult Participants With Advanced Solid Tumors
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Wouter Zandee, Dr. principal investigator
University Medical Center Groningen
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Low iodine diet in people with Differentiated Thyroid Cancer, run by University Medical Center Groningen at 1 site in Netherlands.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 6 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Netherlands. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Wouter Zandee, Dr. (+31503613731, w.t.zandee@umcg.nl), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Iodine uptake (time frame: 7 days). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 Feb 2026.