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Surgical Decisions for Thyroid Nodules Often Not Affected By Molecular Testing

NEW YORK (GenomeWeb) – A new study has found that molecular testing of patients' thyroid nodules generally doesn't affect the surgical decisions made.

Distinguishing benign and malignant thyroid nodules can be difficult, and physicians currently draw upon a combination of cytological, radiological, clinical, and patient factors to gauge whether a nodule is suspicious and should be removed. A number of companies have developed molecular tests to analyze DNA mutations or RNA expression levels to aid in making this determination.

However, researchers from Johns Hopkins University School of Medicine found that when they examined the surgical management of patients who'd undergone molecular testing, such testing only occasionally affected surgical decision-making, as they reported in JAMA Otolaryngology-Head & Neck Surgery today. And in those cases where molecular testing did affect surgical decisions, they uncovered evidence of overtreatment.

"Diagnostic molecular testing should not be used reflexively or in isolation to drive clinical decision-making in patients with thyroid nodules," Hopkins' Ralph Tufano and his colleagues wrote in their paper. "These tests should only be considered once patient, clinical, radiological, and cytological factors are weighed in a balanced manner and it is determined that a molecular test result would appropriately alter the treatment plan."

He and his colleagues set up a prospective study that enrolled consecutive patients seen by five thyroid surgeons at Hopkins between April 2014 and March 2015. Of these 688 patients, 140 had undergone diagnostic molecular testing — either an RNA-based gene expression classifier from Veracyte; a DNA-based somatic mutation panel from Asuragen, ThyroSeq, or Quest; or BRAF V600E mutation analysis with or without RAS or RET/PTC alterations — before their surgical consultation. The nearly 80 percent that hadn't undergone molecular testing served as a control group.

Previously, the thyroid surgeons had developed a management algorithm for handling thyroid nodule cases that draws on symptoms, nodule size, and family history to guide treatment. This, the authors noted, enabled them to determine whether the molecular test affected surgical management. They further collected this data in real-time using an interface developed for an Apple iPad. If surgeons' recommendations differed from that of the algorithm, the interface prompted them to enter why.

The surgeons' treatment approaches deviated from that of the treatment algorithm for 12.9 percent of the patients who'd undergone testing and for 10.2 percent of the control patients. For the control patients, the surgeons indicated that they'd most commonly altered their approach because of patient preference, nodule size, and ultrasound findings.

For the patient cohort that had undergone testing, those molecular results were cited as the reason for changing treatment in 11 cases, but for nearly 90 percent of those cases, there was no change in treatment plan.

This, Tufano and his colleagues said, indicates that the molecular tests are being overused and for patients for whom the results — no matter what they were — would not alter the surgical plan.

However, in those cases where testing did influence surgical approach, Tufano and his colleagues found that it led to overtreatment. For those 11 patients whose results were cited as the reason for changing treatment, follow-up was recommended for three, while the other eight, a total thyroidectomy, rather than a hemithyroidectomy, was recommended. But for seven of those eight patients, the authors said this was an inappropriate change, as determined by histopathology analysis performed after the surgery.

"[M]olecular profiling is just one of many adjuncts that may be undertaken in the evaluation of a thyroid nodule. … As shown in this study, physicians must continue to use the diagnostic tools available to them when evaluating a thyroid nodule, instead of solely relying on a molecular test or reflexively obtaining one," the authors wrote. "To avoid unnecessary testing, it may be prudent for surgeons to be consulted before the initiation of molecular profiling."