Test May Prevent Unnecessary Thyroid Surgeries

Cancer gene expression classifier identifies malignancies

(RxWiki News) When a suspicious lump or nodule is found on the thyroid, biopsies can be performed to determine whether or not it's cancerous. If there's a question, the next step usually involves surgery.

A new genetic test may save patients unnecessary surgeries by determining the cancer status of thyroid nodules.

"Always ask if the test that's been ordered is necessary."

A large, multi-center study included investigators from the University of Pennsylvania Perelman School of Medicine.

"This test, currently available at Penn Medicine, can help us determine whether these nodules with indeterminate biopsy results are likely to be benign," said Susan Mandel, MD, MPH, professor of medicine at Penn.

Experts calculate that of all the thyroid nodules biopsied, somewhere between 62-85 percent are not cancerous (benign), and 20-35 percent provide inconclusive results.

This test works by classifying the genes. In the case of unclear results, "patients may be able to avoid unnecessary surgeries and lifelong thyroid hormone replacement treatment," Dr. Mandel said.

Estimates are that the test could prevent some 25,000 unnecessary surgeries a year.

The gene-expression classifier is manufactured by Veracyte, Inc., the company that funded this study.

The test was used to evaluate 265 thyroid nodules of indeterminate status. It correctly identified 92 percent (78 of 85) of "suspicious" samples. It accurately ruled out malignancy on 85-95 percent of the samples.

"Though each clinical decision must be individualized, these data suggest consideration of a more conservative clinical approach for patients who have nodules with indeterminate cytologic features on fine-needle aspiration and a benign result on gene-expression classifier testing," Dr. Mandel said.

Results from this study were published June 25 in the New England Journal of Medicine.

Conflicts of interest disclosures were not made available to the public.

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Review Date: 
June 28, 2012