This trial is active, not recruiting.

Condition thyroid neoplasms
Treatment radioactive iodine
Phase phase 3
Sponsor Helsinki University
Collaborator Helsinki University Central Hospital
Start date January 2000
End date October 2004
Trial size 160 participants
Trial identifier NCT00115895, SYTJ001T/2000


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.

United States No locations recruiting
Other Countries No locations recruiting

Study Design

Allocation randomized
Endpoint classification efficacy study
Intervention model parallel assignment
Masking open label
Primary purpose treatment
Low activity of radioiodine, 1,1 GBq
radioactive iodine radioiodine
Radioiodine is radionuclear treatment given in oral capsules in two activies 1,1 and 3,7 GBq
Routine activity of radioiodine, 3,7 GBq
radioactive iodine radioiodine
Radioiodine is radionuclear treatment given in oral capsules in two activies 1,1 and 3,7 GBq

Primary Outcomes

Cumulative number of radioactive iodine administrations
time frame: 15 yrs

Secondary Outcomes

Adverse events
time frame: 15 yrs
Absorbed radiation dose
time frame: 15 yrs
Cancer recurrence
time frame: 15 yrs

Eligibility Criteria

Male or female participants at least 18 years old.

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

Additional Information

Official title Effect of the Radioiodine Dose in Thyroid Ablation- A Randomized Comparison of 1110 MBq to 3700 MBq
Principal investigator Hanna O Mäenpää, M.D. Ph.D.
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
Trial information was received from ClinicalTrials.gov and was last updated in March 2016.
Information provided to ClinicalTrials.gov by Helsinki University.