the role of 68-gallium-dotatate-pet/ct in the imaging of metastatic thyroid cancer

Conditions: Metastic Thyroid Cancer

Summary: background: about 5% to 10% of differentiated thyroid cancers become resistant to standard treatment with radioactive iodine. in these cases, treatment options are limited and generally not effective. researchers want to see if they can better detect thyroid tumors by using a compound called 68gallium-dotatate. this compound may bind to a tumor and make it visible during a positron emission tomography/computed tomography (pet/ct) scan. this information might help guide future research and treatment. objective: to identify the people with thyroid cancer whose tumors have a high uptake of 68gallium-dotatate as analyzed by imaging with pet/ct. eligibility: people ages 18 years and older with thyroid cancer that has spread outside of the thyroid. design: participants will have a medical exam. they will give blood and urine samples. some samples will be used for research. participants will have imaging scans that follow standard of care. these scans may include: ct scan of the neck, chest, abdomen, and pelvis bone scan magnetic resonance imaging of the brain, spine, or liver 18-fdg-pet/ct as needed participants will have a pet/ct scan. they will get an intravenous (iv) line. they will get an iv injection of 68gallium-dotatate. it contains radioactive tracers. the pet/ct scanner is shaped like a large donut. it contains crystals. the crystals pick up small radiation signals that are given off by the tracers. the ct part of the scan uses low-dose x-rays. the pictures made by the scanner show where the tracers are in the body. the session will last 90 minutes. participation will last for about 3 months.

the study is designed to identify the patients with metastatic radioactive iodine (rai) non-avid or non-responsive thyroid cancer rai non-responsive hurthle cell thyroid cancer (htc), differentiated thyroid cancer (dtc) and metastatic medullary thyroid cancer (mtc), whose tumors are characterized by a high expression of somatostatin receptors type 2 (sstr2) by a one-time experimental imaging using 68gallium(68ga)-dotatate positron emission tomography/computed tomography (pet/ct) scan. participants will also undergo standard of care imaging per ata guidelines. both the experimental 68ga-dotatate pet/ct scan and the standard of care imaging will be performed within a 3 month timeframe. the main goal is to compare the prevalence of patients with metastatic rai-non-avid or rai-non-responsive thyroid cancer whose tumors are characterized by a high sstr2 expression by imaging with 68ga-dotatate pet/ct between three groups: (1) group htc - the molecularly and histologically unique subtype of differentiated thyroid cancer (dtc) - hurthle cell thyroid cancer (htc), (2) group dtc - patients with remaining histological types of dtc, and (3) group mtc -- patients with metastatic thyroid cancer of neuroendocrine origin - medullary thyroid cancer (mtc). the second goal of this study is to analyze the associate between the 68ga-dotatate uptake and molecular signature of thryoid cancer and tumor volume, and to create a repository of data for future research in thyroid cancer.

Eligibility criteria:
* inclusion criteria: patients with htc, dtc, and mtc will be identified by the investigators. the potential candidates for the study will be screened for eligibility to participate in the study and invited to sign the research 68gallium-dotatate pet/ct imaging informed consent form in order to be eligible to participate in this study, an individual with dtc (including htc) must meet all of the following criteria: 1. male or female, aged \>=18 years. 2. patients with established thyroid cancer diagnosis presenting with either: 1. locally advanced or distant metastases, which are rai-non-avid based on the \[123\]i or \[131\]i diagnostic or post-treatment whole body scan (wbs) or 2. patients with rai-non-responsive disease, who have the evidence of disease progression defined by recist 1.1 criteria after therapy with rai. in order to be eligible to participate in this study, an individual with mtc must meet all of the following criteria: 1. male or female, aged \>=18 years. 2. patients with locally advanced or metastatic mtc or patients suspected of locally advanced or metastatic mtc with calcitonin level \> 500 pg/ml. exclusion criteria: subjects with either htc, dtc, or mtc who meet any of the following criteria will be excluded from participation in this study: 1. pregnancy or lactation by self-report. 2. serious underlying medical conditions that restrict diagnostic testing or therapy such as renal failure, congestive cardiac failure or active coexisting non-thyroid carcinoma; 3. patients unable to give informed consent.

Keywords: thyroid cancer metastases ga68-dotatate somatostatin receptors positron emission tomography