Early recurrence of thyroid cancer may be detectable using a blood test to detect a protein called 'Thyroglobin"(Tg) according to a study published by researchers at The Ohio State University Comprehensive Cancer Center and Arthur G. James Cancer Hospital and Richard J. Solove Research Institute. The findings were published June 21 online in the Journal of Clinical Endocrinology & Metabolism.
Thyroglobulin (Tg) is made by thyroid-cancer cells. The measurement is taken after a person is injected with a relatively new drug known as thyrotropin alfa, or Thyrogen.
The drug allows Tg testing without the sometimes debilitating side effects of hypothyroidism that otherwise accompany the test when stimulation testing is done.
"We were surprised to find that even with relatively low thyroglobulin levels, and even when there is no sign of a tumor, about 80 percent of patients had a recurrence of their cancer within three to five years," says first author Richard T. Kloos, associate professor of internal medicine and of radiology.
"This indicates that we are detecting these tumors very early, and that time and diligence may be needed to find them."
"Currently, some thyroid-cancer treatment guidelines say that these patients may never need further testing, but our data contradict that," says Kloos, co-director of the Thyroid Cancer Unit at the OSU CCC - James.
Thyroid cancer requires surgical removal of the gland followed by treatment with radioactive iodine. As the thyroid gland is removed it is essential to give replacement with the hormone thyroxin. This the patient has to take for rest of their life. Till the recent past, Tg testing required that patients had to stop taking their synthetic thyroid hormone several weeks before the test.
"That worked fairly well, except that some people became miserable after they stopped taking their synthetic thyroid hormone and became hypothyroid," Kloos says. "Some patients claimed that they'd rather die of their disease than go through that regularly."
Hypothyroid state leads to fatigue, weight gain, constipation, mental dullness, lethargy, depression and other symptoms.
When thyroid cells are removed the Tg level comes to zero, however its presence later signals a possible return of the disease. Thyrogen, approved for use in 1998, allowed people to have a stimulated Tg test and continue taking the synthetic hormone.
The present study sought to help interpret the results of the Thyrogen-assisted Tg test. It involved 107 patients (88 women and 19 men; average age 36 years) treated for papillary, follicular or Hurthle cell thyroid cancer.
Following surgery and radioactive iodine treatment and the patients were injected with Thyrogen and tested for Tg levels between January 1999 and March 2001.
After an interval of three to five years, the researchers found recurrent tumors in about 80 percent of the patients with Tg levels above 2.0, and in about 2 percent of those with Tg levels below 0.5.
It is estimated 25,690 new cases of thyroid cancer will be detected in 2005, with 19,190 of those expected to occur in women. 1,490 people are expected to die of the disease.
Ernest L. Mazzaferri, OSU emeritus professor and chairman of medicine, was a co-author of the study.
Contact: Darrell E. Ward:[email protected]
614-293-3737, Ohio State University ,