LAKE BUENA VISTA, FLA. – Observation is a reasonable option for managing patients with benign thyroid nodules that display initial low-suspicion ultrasound patterns.
Presented at the International Thyroid Congress, the American Thyroid Association’s new guidelines on the management of thyroid nodules offer specific ultrasound patterns that help distinguish benign nodules from developing malignancy (Thyroid. 2015 Oct. doi: 10.1089/thy.2015.0020]).
Dr. Susan Mandel
They reflect new data obtained from studies conducted in the years since 2009, when the last guidelines were issued, Dr. Susan Mandel said at the meeting, which was held by the American Thyroid Association, Asia-Oceania Thyroid Association , European Thyroid Association, and Latin American Thyroid Society.
“We now know that about 20% of cytologically benign thyroid nodules will grow,” said Dr. Mandel of the University of Pennsylvania, Philadelphia. But very few of those will become malignant. According to a newly published study of 553 patients, 200 must be followed to identify one cancer that would have been missed (Thyroid. 2015 Oct 25;10:1115-20).
The new guidelines reflect findings like these and attempt to balance sensible follow-up while avoiding overtreatment, Dr. Mandel said. Diagnosed thyroid cancers are on the rise in the United States, from about 37,000 in 2009 to about 63,000 last year. But this is not because the cancer itself is more prevalent. More likely, it is the result of the increasing use of sonography or other imaging studies, which allows for earlier diagnosis and treatment. These technologies have a downside as well, leading to overdiagnosis and overtreatment of benign nodules that, most likely, would never undergo malignant transformation, Dr. Mandel said.
Nodules are most likely to grow in younger patients and those with longer follow-up, “which makes sense, as thyroid nodules grow very slowly.” Predominately solid nodules are also more likely to grow than are cystic nodules. Size at baseline is a controversial topic. There is some evidence that subcentimeter nodules are more likely to grow, while larger nodules are less likely.
Worrisome initial ultrasound patterns, however, should throw up a red flag even if the nodule is cytologically negative at baseline, Dr. Mandel said. These patterns are:
• Marked hypoechogeniticy.
• Microcalcifications.
• Irregular, microlobulated margins.
• Taller-than-wide shape.
• Incomplete or peripheral calcification.
These nodules should undergo a repeat ultrasound and a repeat ultrasound-guided fine needle biopsy within 6-12 months of the initial assessment, the guidelines recommend.
For nodules of any state, if (1) there is sonographic evidence of growth (20% increase in at least 2 nodule dimensions with a minimal increase of 2 mm or (2) more than 50% change in volume) or (3) development of new suspicious sonographic features, there should be an additional fine-needle biopsy. “Although the risk of malignancy after two benign cytology results is virtually zero, routine repeat biopsy is not a viable or cost-effective option because of the low false negative rate,” the document notes.
Small nodules (less than 1 cm) that have very low-suspicion ultrasound patterns (including spongiform nodules) don’t require routine follow-up sonograms. Nor do nodules larger than 5 mm without high-suspicion findings.
The guidelines also offer recommendations on treatment. There is no need to offer routine therapy with thyroid stimulating hormone (TSH) for benign nodules. “Though modest responses to therapy can be detected, the potential harm outweighs benefit for most patients,” the document states.
If benign nodules grow, surgery could be an option if they become large (greater than 4 cm), or cause compression or structural symptoms – or if there is clinical concern, although the document does not specify exactly what that could be.
Patients with growing nodules that are benign after a second biopsy should be regularly monitored. Most asymptomatic nodules demonstrating modest growth should be followed without intervention,” it says.
Recurrent benign cystic thyroid nodules may be treated surgically or with ethanol ablation, but asymptotic cystic nodules may be followed conservatively There are no data to guide the use of thyroid hormone treatment for benign nodules, even if they do grow.
The guidelines also offer recommendations for initial serum and molecular studies, and treatment for follicular and differentiated thyroid cancers.
Dr. Mandel had no financial disclosures.