Conference Coverage
Accuracy of gene test for thyroid nodules questioned
BALTIMORE – Biopsy results from a commercially available genetic test for ruling out malignancy of thyroid nodules may not provide reliable...
BOSTON – Normalizing the serum thyroglobulin level by thyroid nodule size in patients surgically treated for a thyroid nodule produced a strongly significant link between the level of this marker and nodule malignancy in a review of nearly 200 patients treated at any of three Montreal centers.
After normalization, the serum thyroglobulin of patients with a malignant nodule averaged 51 mcg/L*cm, more than double the average 23 mcg/L*cm among patients with benign nodules, Neil Verma, MD, said at the World Congress on Thyroid Cancer.
Mitchel L. Zoler/Frontline Medical News
Dr. Neil Verma
But the senior investigator on the study said that, even if the MTNS+ gets a little more accurate by using a nodule size-normalized serum thyroglobulin level, the clinical utility of the MTNS+ will soon be completely eclipsed by widespread reliance on molecular tests, whereas the MTNS+ combines many clinical and conventional laboratory measures. It‘s only a matter of cost, said Richard J. Payne, MD, a head and neck surgeon at McGill.
Dr. Richard J. Payne
Routine reimbursement for molecular diagnostic tests for the malignancy of thyroid nodules was discussed at a recent meeting of Canadian head and neck surgeons, who decided to lobby provincial governments to try to get it covered, according to Dr. Payne. “I’d be very surprised if we don’t have government coverage within 4-5 years,” in part because the cost for molecular testing will likely fall significantly in that time frame, he predicted.
The analysis reported by Dr. Verma included 196 patients with thyroid nodules who underwent a partial or total thyroidectomy at any of three McGill teaching hospitals during 2010-2015. He determined the benign or malignant status of their nodules based on their histology. The analysis he presented also showed that malignancy had no clear relationship to nodule size. Nodules that were less than 2 cm in diameter were about as likely to be malignant as were those that were 3 cm or larger in diameter, Dr. Verma reported.
Size-normalized serum thyroglobulin will now be incorporated into the MTNS+, which will be the fourth change to the original MTNS scoring system since it was developed more than a decade ago, noted Dr. Payne. But, while the MTNS+ allows better prediction of malignant potential than does the Bethesda system for evaluating nodule cytopathology in a fine-needle aspirate, it still falls short of molecular testing in its predictive accuracy, Dr. Payne said.
Dr. Verma and Dr. Payne had no disclosures.
On Twitter @mitchelzoler