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The Dose of Radioactive Iodine Needed to Ablate the Thyroid Remnant Left Behind After Thyroidectomy

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00115895
Recruitment Status : Unknown
Verified March 2018 by Hanna Mäenpää, University of Helsinki.
Recruitment status was:  Active, not recruiting
First Posted : June 27, 2005
Last Update Posted : March 2, 2018
Helsinki University Central Hospital
Information provided by (Responsible Party):
Hanna Mäenpää, University of Helsinki

Brief Summary:
The thyroid cells take up iodine, and radioactive iodine is commonly used to irradiate residual thyroid tissue and thyroid cancer following surgical removal of the thyroid gland (thyroidectomy). A whole body radioactive iodine scanning is usually carried out after thyroidectomy to assess the amount of thyroid tissue left behind at surgery (that might still contain cancer), and to evaluate the presence of iodine avid lesions elsewhere in the body (that might be cancer metastases). A large dose of radioactive iodine is often given, still the optimal iodine dose to ablate the thyroid remnant after surgery is not known. In this study, two radioactive iodine doses are compared in the ablation of the thyroid remnant, a smaller (1110 MBq) dose and a larger (3700 MBq) dose. The study participants are randomly allocated using a 1:1 ratio to receive either the smaller or the larger radioactive iodine dose. These treatments are compared for safety, adverse effects, and the need for subsequent repeat treatments. The individual absorbed radiation doses are measured. The study hypothesis is that fewer repeat radioiodine treatments might be needed after the larger dose, but the larger dose might be associated with a higher frequency of adverse events.

Condition or disease Intervention/treatment Phase
Thyroid Neoplasms Drug: Radioactive iodine Phase 3

Detailed Description:

The study participants are randomly allocated to receive either a 1110 MBq or a 3700 MBq dose of radioiodine (131I) approximately 5 weeks after thyroidectomy. Thyroxin substitution is initiated only after administration of radioactive iodine. Treatment efficacy is monitored using serum thyroglobulin measurements and whole body radioiodine scanning. The absorbed radiation dose at the thyroid remnant and the biological half-life of radioactive iodine are measured with SPECT, 131I iodine detector and a Geiger counter.

Treatment related adverse events are collected using structured forms 4 to 5 days, 2 weeks and 3 months after administration of radioiodine. The need for a repeat treatment is assessed 4 to 6 months after the first administration of radioiodine. The criteria for a repeat radioiodine treatment are serum thyroglobulin > 1 ug/L and/or presence of abnormal radioiodine uptake in a whole body radioiodine scanning, which is carried out following a 4-week interruption of thyroxin supplementation or following administration of rhTSH.

Number of patients: 160

Aims of the study:

  • To find out weather the risk for second radioiodine treatment differs with two dose levels of radioiodine: 1110 MBq or 3700 MBq.
  • To study possible differences in the adverse effects in the treatment groups. Also days at hospital are counted.
  • To analyse the effect of absorbed radiation dose to the treatment results

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 160 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Effect of the Radioiodine Dose in Thyroid Ablation- A Randomized Comparison of 1110 MBq to 3700 MBq
Study Start Date : January 2000
Actual Primary Completion Date : October 2004
Estimated Study Completion Date : September 2020

Resource links provided by the National Library of Medicine

Drug Information available for: Iodine

Arm Intervention/treatment
Experimental: Radioactive iodine 1,1 GBq
Low activity of radioiodine, 1,1 GBq
Drug: Radioactive iodine
Radioiodine is radionuclear treatment given in oral capsules in two activies 1,1 and 3,7 GBq
Other Name: radioiodine

Radioactive iodine 3,7 GBq
Routine activity of radioiodine, 3,7 GBq
Drug: Radioactive iodine
Radioiodine is radionuclear treatment given in oral capsules in two activies 1,1 and 3,7 GBq
Other Name: radioiodine

Primary Outcome Measures :
  1. Cumulative number of radioactive iodine administrations [ Time Frame: 15 yrs ]

Secondary Outcome Measures :
  1. Adverse events [ Time Frame: 15 yrs ]
  2. Absorbed radiation dose [ Time Frame: 15 yrs ]
  3. Cancer recurrence [ Time Frame: 15 yrs ]

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion criteria:

  • Total or near total thyroidectomy performed for papillary or follicular thyroid cancer
  • R0-1 resection, no macroscopic cancer left behind at surgery
  • Physically and emotionally able to undergo radioiodine treatment
  • A written informed consent

Exclusion criteria:

  • Pregnancy
  • Physical or psychiatric illness that may deteriorate during the isolation period required by radioiodine therapy

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00115895

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Helsinki University Central Hospital, Department of Oncology
Helsinki, Finland, FIN-00029HUS
Sponsors and Collaborators
University of Helsinki
Helsinki University Central Hospital
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Principal Investigator: Hanna O Mäenpää, M.D. Ph.D. Deputy Chief Physician
Additional Information:
Publications automatically indexed to this study by Identifier (NCT Number):
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Responsible Party: Hanna Mäenpää, Chief of Department, University of Helsinki Identifier: NCT00115895    
Other Study ID Numbers: SYTJ001T/2000
First Posted: June 27, 2005    Key Record Dates
Last Update Posted: March 2, 2018
Last Verified: March 2018
Keywords provided by Hanna Mäenpää, University of Helsinki:
serum thyroglobulin
whole body radioiodine scanning
Additional relevant MeSH terms:
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Thyroid Neoplasms
Thyroid Diseases
Endocrine System Diseases
Endocrine Gland Neoplasms
Neoplasms by Site
Head and Neck Neoplasms