Comparison of Dosimetry After rhTSH or Withdrawal of Thyroid Hormone in Metastatic or Locally Advanced Thyroid Cancer

Gustave Roussy, Cancer Campus, Grand Paris4 enrolled

Overview

Metastases of thyroid cancer with iodine uptake are treated with repeated activity of I-131 administered after thyroid hormone withdrawal. The goal of thyroid hormone withdrawal is to treat patients with elevated thyrotropin stimulated hormone (TSH), a hormone secreted by the pituitary, a gland just located under the brain. Another way to obtain elevated TSH levels is to perform intramuscular injection of recombinant human TSH, a hormone produced pharmaceutically. The goal of this study is to know whether the radioiodine uptake by the metastases is similar after rhTSH administration or after thyroid hormone withdrawal.

Patients will undergo a rhTSH stimulation, staying on thyroid hormone treatment. Following 2 administration of rhTSH an injection of I-124 will be performed. Positron emission tomography with computed tomography scans (PET/CT), blood tests, and measurements of whole body radioactivity will occurred during the 4 to 96 hours following I-124 administration in order to perform dosimetry (i.e.) to estimate the radiation dose delivered to the metastases. After 4 weeks under thyroid hormones patients will undergo thyroid hormone withdrawal and a new administration of I-124 will be performed. The same dosimetry study will be realized with PET/CT, blood tests, and measurements of whole body radioactivity. A therapeutic activity of I-131will then be administered followed by whole body scan realized 24 to 72 hours after the administration of I-131. Dosimetry studies will be compared in order to determine whether rhTSH stimulation can replace thyroid hormone withdrawal for the treatment of distant metastases.

Study Type

INTERVENTIONAL

Allocation

Masking

NONE

Enrollment

Conditions

Thyroid Cancer

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: 1. Patients with thyroid cancer and known measurable (\>1cm) distant metastases demonstrating radioiodine uptake on a previous whole body scan 2. Patients planned for a therapeutic activity of 131I after thyroid hormone withdrawal 3. Age \>18 years 4. Previous treatment with radioiodine more than 6 months before inclusion. 5. Serum TSH level \<0.5 mU/L 6. Normal renal function with a creatinine clearance estimation using the Cockcroft-Gault formula \> 60 ml/ml 7. Effective means of contraception for female patient, at risk of pregnancy 8. Written informed consent Exclusion Criteria: 1. Patients whose majority of tumoral lesions disclose FDG uptake without radioactive iodine uptake 2. Iodine excess (\< 50 μg/dl) 3. Large or diffuse bone or brain metastases 4. Patients with multiple small tumor foci less than 1 cm in diameter, such as miliary spread to the lungs 5. Patients already included in a therapeutic trial with an experimental medicine 6. Pregnancy and breast feeding patients 7. Subject with any kind of disorder that compromises the ability of the subject to give written informed consent and/or to comply with study procedures 8. Treatment with antivitamin k

Outcomes

Primary Outcomes

the 124 I uptake after TSH stimulation

For each patient, the 124 I uptake after TSH stimulation (a marker of radiation absorbed dose) will be compared to the uptake after thyroid withdrawal in all lesions (up to 16 lesions per patient maximum). A decrease in the residence time of more than 2.5 fold in 25% or more of the lesions is considered unacceptable.

Time frame: 4 to 96 hours

Secondary Outcomes

The activity of 131I that should be administered according to each TSH stimulation method

To determine the activity of 131I that should be administered following rhTSH to deliver a radiation absorbed dose similar to that delivered under hypothyroid conditions. A calculated activity above 250mCi is considered unacceptable.

Time frame: 96 hours

Radiation exposure of the blood

The radiation exposure of the blood, calculated from blood samples and whole body radioactivity measurements