Friday, February 8, 2013

The Meaning of Thyroglobulin Levels for Thyroid Cancer Survivors

The Meaning of Thyroglobulin Levels for Thyroid Cancer Survivors
Sunday, 20 January 2013 11:23
Thyroglobulin, also known as "Tg", is a prohormone (protien) that is produced by thyroid cells or thyroid cancer cells and released into the blood.  Thyroglobulin can be measured with a simple blood test.  The detection of thyroglobulin is proof of the presence of thyroid cells.  This test is very useful when monitoring thyroid cancer patients after surgery and radioactive iodine-131 ablation treatment.  

For thyroid cancer survivors the goal is to have a stable very low thyroglobulin or undetectable level of thyroglobulin.  This would indicated no thyroid cancer cells.
It is also important that one's thyroglobulin levels don't increase over time.  If one's thyroglobulin levels do increase over time this could indicate a recurrence or metastasis of one's thyroid cancer.
Below is the percentage of recurrence within five years after radioactive Iodine-131 ablation for differentiated thyroid carcinoma in one study conducted by Kloos and Mazzaferri.
Thyroglobulin (Tg) less than .5 ng/ml        = 1.6% recurrence of thyroid cancer5
Thyroglobulin (Tg) 0.6 to 2.0 ng/ml           = 5.5% recurrence of thyroid cancer5
Thyroglobulin (Tg) greater than 2.0 ng/mL = 80% recurrence of thyroid cancer5
It is recommended that thyroid cancer survivors thyroglobulin levels be monitored every 6 to 12 month to detect recurrences or metastasis of thyroid cancer.

5.  Kloos RT, Mazzaferri El, A Single Recombinant Human Thyrotropin-Stimulated Serum Thyroglobulin Measurement Predicts Differentiated Thyroid Carcinoma Metastases Three to Five years Later. Endocrinology Metabolism 2005, 90:1440
Last Updated on Sunday, 20 January 2013 11:44

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