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

March 1, 2018 updated by: Hanna Mäenpää, University of Helsinki

Effect of the Radioiodine Dose in Thyroid Ablation- A Randomized Comparison of 1110 MBq to 3700 MBq

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.

Study Overview

Status

Unknown

Conditions

Intervention / Treatment

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

Study Type

Interventional

Enrollment (Actual)

160

Phase

  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Finland
      • Helsinki, Finland, FIN-00029HUS
        • Helsinki University Central Hospital, Department of Oncology

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / 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 Names:
  • radioiodine
Other: 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 Names:
  • radioiodine

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Cumulative number of radioactive iodine administrations
Time Frame: 15 yrs
15 yrs

Secondary Outcome Measures

Outcome Measure
Time Frame
Adverse events
Time Frame: 15 yrs
15 yrs
Absorbed radiation dose
Time Frame: 15 yrs
15 yrs
Cancer recurrence
Time Frame: 15 yrs
15 yrs

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Helsinki

Collaborators

Helsinki University Central Hospital

Investigators

  • Principal Investigator: Hanna O Mäenpää, M.D. Ph.D., Deputy chief physician

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

January 1, 2000

Primary Completion (Actual)

October 1, 2004

Study Completion (Anticipated)

September 1, 2020

Study Registration Dates

First Submitted

June 26, 2005

First Submitted That Met QC Criteria

June 26, 2005

First Posted (Estimate)

June 27, 2005

Study Record Updates

Last Update Posted (Actual)

March 2, 2018

Last Update Submitted That Met QC Criteria

March 1, 2018

Last Verified

March 1, 2018

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • SYTJ001T/2000

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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