Lack of accrual

The purpose of this study is to find out whether people who have had thyroid cancer develop resistance to treatment with thyroid hormones after having received high doses of thyroid drugs for many years.

Inclusion Criteria:

• Age 18 or older

• Due to a diagnosis of thyroid cancer, patient underwent a total thyroidectomy based on pathology.

• No evidence of active disease based on routine surveillance testing showing no suspicious findings on neck ultrasound and low thyroglobulin levels (≤1.0 ng/ml) with negative thyroglobulin antibodies within one year of study enrollment. For the study patients, this response can be evaluated after five years of TSH suppression. For control subjects, this response can be evaluated after two years of surveillance.

• Two groups:

  • 8 patients with a history of thyroid hormone suppression (TSH<0.5 mU/L) for at least 5 years
  • 8 patients with no history of TSH suppression

• Normal TSH level based on the laboratory reference range for at least 6 months at the time of study enrollment.

• Blood pressure range of >90/60 and <180/100. Patients may be included in the study if blood pressure has been treated with medication and normalized.

Exclusion Criteria:

• Patient reported history of symptomatic heart disease including unstable angina or NYHA stage III or IV heart failure.
• Patient reported history of one of the following cardiac arrhythmias: atrial fibrillation, atrial flutter, paroxysmal supraventricular tachycardia, ventricular fibrillation, or ventricular tachycardia.
• Patient reported history of uncontrolled hypotension (<90/60) or hypertension (>180/100).
• History of renal dysfunction with creatinine more than 1.5 times the upper limit of normal based on recent laboratory testing
• Known hypersensitivity to the drug
• Pregnant or breast feeding
• Prior history of seizures or brain damage
• Patients on chronic therapy with levodopa
• Patients on therapeutic doses of acetylsalicylic acid (2 - 3.6 gm/day)
• Patients with conditions that result in disruption of the hypothalamic-pituitary axis (i.e. hypophysectomy, hypopituitarism, pituitary tumor/surgery, head irradiation, or head trauma).

Memorial Sloan Kettering Cancer Center supports the international committee of medical journal editors (ICMJE) and the ethical obligation of responsible sharing of data from clinical trials. The protocol summary, a statistical summary, and informed consent form will be made available on clinicaltrials.gov when required as a condition of Federal awards, other agreements supporting the research and/or as otherwise required. Requests for deidentified individual participant data can be made beginning 12 months after publication and for up to 36 months post publication. Deidentified individual participant data reported in the manuscript will be shared under the terms of a Data Use Agreement and may only be used for approved proposals. Requests may be made to: crdatashare@mskcc.org.