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

Thyroid Neoplasms Clinical Trial

Official title:

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

Clinical Trial Details — Status: Active, not recruiting

Administrative data

• NCT number: NCT00115895
• Other study ID #: SYTJ001T/2000
• Status: Active, not recruiting
• Phase: Phase 3
• First received: June 26, 2005
• Last updated: March 1, 2018
• Start date: January 2000
• Est. completion date: September 2020

Study information

• Verified date: March 2018
• Source: Helsinki University
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial 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.

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

Recruitment information / eligibility

• Status: Active, not recruiting
• Enrollment: 160
• Est. completion date: September 2020
• Est. primary completion date: October 2004
• Accepts healthy volunteers: No
• Gender: All
• Age group: 18 Years and older

Eligibility

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

Related Conditions & MeSH terms

• Thyroid Diseases
• Thyroid Neoplasms

Intervention

Drug:
• Radioactive iodine
Radioiodine is radionuclear treatment given in oral capsules in two activies 1,1 and 3,7 GBq

Locations

Country	Name	City	State
Finland	Helsinki University Central Hospital, Department of Oncology	Helsinki

Sponsors (2)

Lead Sponsor	Collaborator
Helsinki University	Helsinki University Central Hospital

Country where clinical trial is conducted

Finland, 

References & Publications (1)

Roos DE, Smith JG. Randomized trials on radioactive iodine ablation of thyroid remnants for thyroid carcinoma--a critique. Int J Radiat Oncol Biol Phys. 1999 Jun 1;44(3):493-5. Review. — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Cumulative number of radioactive iodine administrations		15 yrs
Secondary	Adverse events		15 yrs
Secondary	Absorbed radiation dose		15 yrs
Secondary	Cancer recurrence		15 yrs

External Links

•   Helsinki University Central Hospital