The good news about thyroid cancer is that treatment for it is relatively easy. Surgeons remove the thyroid gland and follow with a dose of radioactive iodine designed to destroy lingering cells. The bad news is that sometimes not all the cells are caught and the subsequent yearly monitoring that must follow causes patient anxiety and physical illness. Current monitoring methods also carry a slight risk of accelerating tumor growth.
Now a study at Johns Hopkins suggests a new way to safely and effectively detect left-over thyroid cells.
The test relies on the researchers' discovery that stray human thyroid cells can circulate in the bloodstream. It also extends the use of PCR (polymerase chain reaction) from a technique important in gene discovery and cancer diagnosis to one for patient monitoring -- a use "that will likely become standard in the near future," says endocrinologist Michael Levine, M.D., who led the research team. The study was published in this month's Journal of Clinical Endocrinology and Metabolism.
Historically, physicians look for remaining thyroid cells either by having patients take radioactive iodine, which concentrates in the thyroid gland and can be detected by scanners; or by analyzing blood for thyroglobulin, a protein made by thyroid cells. The more thyroglobulin in the bloodstream, the reasoning goes, the more thyroid cells. Physicians need both methods to pick up leftover thyroid cells that could be cancerous.
But because both tests deliver false results if patients' blood contains
thyroid hormone, those under treatment and scheduled for monitoring must stop
taking the thyroid hormone pills they've used daily since their thyroid gland
removal. The resulting low levels of the hormone, says Levine, "quickly bring
on the symptoms of hypothyroidism: People are easily tired and often depressed,
their skin becomes dry, they get forgetful, their heart rate decrea
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Contact: Marjorie Centofanti
mcentofanti@jhmi.edu
410-955-8725
Johns Hopkins Medical Institutions
1-Dec-1998