A Retrospective Observational Study Comparing Two Different Treatment Options in Thyroid Cancer Patients With T4 Tumours

Study Overview
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Brief Summary
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The study is to demonstrate non-inferior thyroid remnant first ablation success of Thyrogen and 131I compared to thyroid hormone withdrawal (THW) and 131I in patients with T4 tumour based on historical diagnostic whole body scan (DxWBS) records.

Official Title
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A Retrospective, Non-interventional Study of Patients With T4 Tumours Comparing the Thyroid Remnant Ablation Success Following Thyrogen and 131I Administration Versus Thyroid Hormone Withdrawal and 131I Administration

Conditions
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Thyroid Cancer

Intervention / Treatment
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* Drug: Thyrogen
* Drug: 131I
* Other: Thyroid Hormone Withdrawal


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Historical records from patients who meet all of the following criteria will be eligible for inclusion in this retrospective evaluation: Male or female patients living or deceased, aged 18 years or older at the time of first ablation for thyroid cancer. Diagnosed with a well-differentiated T4 tumour (defined as a primary tumour of any size that extends beyond the thyroid capsule [this may be referred to as TNM classification T4, N0-1, M0-1]). This excludes unusual histological types such as oncocytic (Hurthle cell carcinoma), tall cell, sclerosing or cribriform thyroid cancers. Undergone a near-total or total thyroidectomy on or after 01 January 2000 Undergone first ablation of thyroid remnants with high activity 131I (≥28 mCi or ≥ 1.036 GBq). Undergone first 131I ablation for the T4 tumour using either Thyrogen (0.9 mg IM on 2 consecutive days) or THW stimulation. This excludes use of non-standard Thyrogen regimens (i.e., had a regimen of Thyrogen other than the standard 0.9 mg IM on 2 consecutive days or received Thyrogen in combination with THW). Historical records are available confirming ablation results by: DxWBS using small activity (≥2 mCi or 74 MBq) of iodine 131I (or 123I) performed at least 6 months after administration of the first ablation activity of 131I and/or Stimulated Tg measured at least 6 months after administration of the first ablation activity of 131I. Exclusion Criteria: Historical records from patients who meet any of the following criteria will be excluded from this retrospective evaluation: Received propylthiouracil, methimazole, vitamins or supplements containing kelp or iodine (taking a multivitamin that does not contain iodine or kelp is acceptable), medications that significantly affect iodine handling such as high dose corticosteroids, high dose diuretics, or lithium in the 45 days before administration of first ablative activity of 131I. Received any iodine-containing contrast agents within 3 months prior to first ablative activity of 131I administered. Used amiodarone within the 2 years prior to first ablative activity of 131I administered.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Thyrogen and 131I<br>Patients were previously treated with Thyrogen in conjunction with a high ablative activity of 131I. | Drug: Thyrogen<br>* 0.9 mg IM, administrated for 2 consecutive days<br>Drug: 131I<br>* 28 mCi or ≥ 1.036 GBq.<br>|
| Thyroid Hormone Withdrawal and 131I<br>Patients were previously treated with Thyroid hormone withdrawal (THW) in conjunction with a high ablative activity of 131I. | Drug: 131I<br>* 28 mCi or ≥ 1.036 GBq.<br>Other: Thyroid Hormone Withdrawal<br>* Stop taking hormone therapy<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| First ablation success rate by Diagnostic Whole Body Scan (DxWBS) |  | at least 6 months after administration of first ablation activity of 131I | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| First ablation success rate based on stimulated Thyroglobulin (Tg) levels |  | at least 6 months after administration of first ablation activity of 131I | 
| First ablation success rate based on historical records |  | at least 6 months after administration of first ablation activity of 131I | 
| Number of adverse events of Thyrogen and 131I arm and THW and 131I arm | Exploratory safety assessment in patients with T4 tumour for first ablation of thyroid remnants based on historical records. | Within 30 days of treatment. |