New Evidence-Based Guidelines on Thyroid Cancer

Reprinted from Oncology Times, May 25, 2006.

New guidelines published by the American Thyroid Association hope to offer stronger evidence on which to base diagnosis and treatment of thyroid nodules and thyroid cancer.

Unlike the organization’s original guidelines, which were based mostly on expert opinion, these updated guidelines use an evidence-based approach that included a comprehensive review of the medical literature followed by recommendations for diagnosis and treatment based on the quality of the studies found.

“Every recommendation has a level of evidence that is put next to it that describes whether we recommend it or don’t recommend it based on the amount of evidence supporting it,” said David S. Cooper, MD, Director of the Division of Endocrinology at Sinai Hospital of Baltimore, who chaired the Task Force that wrote the guidelines and is the President-Elect of the American Thyroid Association.

“The older guidelines did not have any of this,” he added. “They were just a set of recommendations based on expert opinion.”

Evidence from well-designed, well-conducted studies that directly evaluated the effects on health outcomes was considered the highest quality evidence and rated an A (strongly recommends) or F (strongly recommends against).

One area that was rated an F in these new guidelines, and which represented a change from the 1996 guidelines, was the recommendation for follow-up care for patients with benign thyroid nodules.

“The guidelines now ‘strongly recommend against’ levothyroxine-suppression therapy for benign thyroid nodules, at least in the absence of nodule growth,” said Ronald Cohen, MD, Assistant Professor of Medicine in the Section of Endocrinology at the University of Chicago.

‘The guidelines do a nice job of identifying unresolved areas and differentiating the types of evidence on which recommendations are based.’

New Roles for Diagnostic Tools

The updated guidelines also provide new roles for diagnostic tools including recombinant human serum thyrotropin (rhTSH), ultrasound, and PET/CT scans.

For example, along with playing an important role in identifying recurrent disease in the neck of patients with established thyroid cancer, the updated guidelines also emphasize that ultrasound is helpful in the evaluation of thyroid nodules, to show that the palpable abnormality represents a thyroid nodule and to identify high-risk characteristic, Dr. Cohen noted.

Few Randomized Treatment Trials

In terms of therapy, however, the recommendations offered by the updated guidelines remain largely based on expert opinion, which carries a C (recommends) or D (recommends against) rating. This is largely due to the lack of randomized clinical trials, which provide the strongest evidence, on therapy options in thyroid cancer.