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Study Comparing Two Treatment Strategies for Intermediate-Risk Thyroid Cancer Using Sodium Iodide (131I) in Patients with Post-Surgery Evaluation

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying a type of thyroid cancer known as intermediate-risk differentiated thyroid cancer. The trial is comparing two different strategies for using a treatment called radioiodine, which involves a substance known as sodium iodide (131I). This treatment is given in the form of capsules. The purpose of the study is to determine if a strategy guided by specific post-surgery tests is as effective as a standard approach in achieving a good response in patients.

Participants in the study will be randomly assigned to one of two groups. One group will receive radioiodine treatment based on a routine schedule, while the other group will have their treatment decisions guided by tests done after surgery. These tests include measuring a protein in the blood called thyroglobulin (Tg) and using a special imaging test called diagnostic RAI scintigraphy. The study will follow participants for several years to see how well each strategy works in treating the cancer.

The trial aims to assess the response to treatment at different time points, such as one, three, and five years after starting the study. It will also look at the quality of life, anxiety, and any side effects related to the treatment. The study will help determine if the guided approach can provide similar or better outcomes compared to the standard method, potentially leading to more personalized treatment plans for patients with this type of thyroid cancer.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Joining the study

    Upon joining the study, the patient is required to have undergone a total thyroidectomy, which is the surgical removal of the thyroid gland. This procedure must have been completed within 6 to 14 weeks before the patient is randomized into the trial.

    The patient must have a normal post-operative neck ultrasound or, if the ultrasound is doubtful, a negative cytology and normal thyroglobulin (Tg) value in the fine needle aspiration (FNA) washout fluid.

  2. Step 2

    Randomization

    The patient is randomly assigned to one of two groups: one receiving systematic radioiodine (RAI) treatment and the other receiving RAI treatment based on a post-operative work-up.

    The post-operative work-up involves assessing serum thyroglobulin (Tg) levels and performing a diagnostic RAI scintigraphy, which is an imaging test to check for remaining thyroid tissue or cancer.

  3. Step 3

    Treatment administration

    For patients in the systematic RAI treatment group, sodium iodide (131I) is administered orally in the form of hard capsules. The dosage ranges from 37 to 5550 MBq, depending on the specific needs of the patient.

    Patients in the guided RAI treatment group receive sodium iodide (131I) only if the post-operative work-up indicates it is necessary.

  4. Step 4

    Follow-up assessments

    Patients are monitored for their response to treatment at 1, 3, and 5 years post-randomization. The primary goal is to achieve an excellent response, which includes normal neck ultrasonography and specific thyroglobulin levels.

    Additional assessments include evaluating the quality of life, anxiety, and fear of cancer recurrence through questionnaires. Toxicities affecting the lachrymal, nasal, and salivary glands are also assessed.

  5. Step 5

    Supplemental treatments

    If necessary, supplemental treatments such as additional surgery or RAI administration may be performed within 5 years post-randomization. The response to these treatments is evaluated according to established guidelines.

    The costs associated with these treatments, including consultations, hospitalizations, imaging exams, and transportation, are considered as part of the study.

Who can join the trial?

14 criteria

  • Patients with a specific type of thyroid cancer called differentiated thyroid cancer and classified as intermediate-risk.
  • Patients with papillary thyroid cancer without aggressive subtype, follicular thyroid cancer with less than 4 areas of blood vessel invasion, or Hürthle cell carcinoma.
  • Patients with certain tumor sizes and conditions, such as T1b or T2 with minimal spread outside the thyroid, or T1aN1 with specific lymph node involvement.
  • Patients must sign an informed consent form, which means they agree to participate after understanding the study details.
  • Patients must agree to be monitored once a year for 5 years.
  • Patients must be part of the French social security system.
  • Patients must have had a total thyroidectomy, which is the complete removal of the thyroid gland, with no visible tumor left.
  • The thyroidectomy must have been done 6 to 14 weeks before joining the study.
  • Patients can have or not have anti-thyroglobulin antibodies, which are proteins the body might make against thyroid cells.
  • Patients must not have any known cancer spread to distant parts of the body.
  • A normal neck ultrasound after surgery, or if the ultrasound is unclear, a negative test result and normal thyroglobulin level in a specific fluid test.
  • Patients must have started LT4 treatment, a thyroid hormone replacement, at least 6 weeks before joining the study.
  • Patients must have a Performance Status of 0 or 1, which means they are fully active or have some symptoms but can do light work.
  • Patients must be 18 years or older.

Who cannot join the trial?

3 criteria

  • Patients who do not have intermediate-risk differentiated thyroid cancer. This means the study is only for those with a specific type of thyroid cancer that is considered to have a moderate level of risk.
  • Patients who are not in the specified age range. The study is for certain age groups, so if you are too young or too old, you may not be eligible.
  • Patients who are part of a vulnerable population. This means people who might need special protection or care, like those with certain disabilities or conditions, may not be included.
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Investigated drugs

Radioiodine Treatment (RAI) is a therapy used in the trial to treat patients with intermediate-risk differentiated thyroid cancer. This treatment involves using radioactive iodine to target and destroy thyroid cancer cells. The trial compares two strategies: one where all patients receive RAI treatment systematically, and another where the decision to use RAI is based on specific post-operative evaluations.

What is already known about the treatment

Radioiodine (RAI) Therapy – This treatment is administered orally, typically in the form of a capsule or liquid. It is currently used in the management of thyroid cancer, particularly for patients with intermediate-risk differentiated thyroid cancer. The main therapeutic indication is to eliminate remaining thyroid tissue or cancer cells after surgery. At the molecular level, radioiodine works by being absorbed by thyroid cells, where it emits radiation that destroys these cells. It is classified as a radiopharmaceutical used in nuclear medicine.

Investigated diseases

Differentiated Thyroid Cancer – Differentiated thyroid cancer is a type of thyroid cancer that arises from the follicular cells of the thyroid gland, which produce and store thyroid hormones. It is generally classified into two main types: papillary and follicular thyroid cancer. This cancer typically grows slowly and may not cause noticeable symptoms in its early stages. As it progresses, it can lead to a lump in the neck, changes in voice, difficulty swallowing, or swollen lymph nodes. The disease is often detected through imaging tests or blood tests that measure thyroid function. It is considered one of the more treatable forms of cancer, especially when caught early.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-514603-34-00Protocol codeINTERMEDIATE-01Estimated enrolment368 patientsSponsorCentre Francois Baclesse

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