BACKGROUND
Detection of thyroid cancer has been increasing over the past several decades. A lot of these cancers are microcancers, meaning that they are <1 cm. These microcancers are low risk for spreading outside the thyroid and have not changed the death rate from thyroid cancer, which is very low. Indeed, monitoring these small cancers by ultrasound instead of pursuing surgery, called active surveillance, has become an accepted treatment option. Many of these microcancers are detected after biopsy small thyroid nodules, also <1 cm, that have suspicious features on ultrasound. In general, active surveillance for nodules <1 cm is usually recommended by guidelines, even if these nodules have suspicious features on ultrasound. Biopsy is then recommended only of there is significant growth of the nodule.

This study was done to determine if there is a specific age cutoff that would help predict the risk of significant growth of small suspicious nodules and that can help us advise patients regarding this likelihood and their options.

THE FULL ARTICLE TITLE
Zhuge, L et al 2023. The optimal age threshold for stratifying the risks of disease progression in patients with highly suspicious sub-centimeter thyroid nodules. Ann Surg Oncol 30:5463–5469. PMID: 37061650.

SUMMARY OF THE STUDY
This study was performed in China and looked at 779 adults with highly suspicious thyroid nodules <1 cm. They excluded any patients that had any aggressive finding on ultrasound (extension beyond the thyroid, involvement of nearby lymph nodes, or dangerous location in the neck).

They defined significant growth as enlargement of the nodule by >50% of volume or >3 mm in diameter or new appearance of highly suspicious nodules/lymph nodes. Ultrasounds were performed 1-2 times a year for up to 7 years (most had a 20 month follow up).

Results of the study showed that approximately 7% of patients had nodules that significantly grew during the study and the factors that predicted progression was age <30 and having multiple suspicious nodules. For patients > 30, having multiple suspicious nodules and the presence of thyroiditis were related to significant growth of the nodules.

WHAT ARE THE IMPLICATIONS OF THIS STUDY?
Although there were a small number of patients less than 30 years old in the study, this study suggests that small suspicious nodules in younger patients (<30 years old) should be biopsied, as they seem to be more likely to have significant growth. However, this study also shows that very few small (<1 cm) thyroid nodules show significant growth over time in patient >30 years old, even if they have suspicious ultrasound features, and supports the recommendations that these nodules can be followed without biopsy.

This study is important because although we understand that small suspicious thyroid can be monitored with a very low risk of death, the medical community is trying to find ways to predict which groups of patients will have more aggressive disease than others in order to make better, patient specific recommendations.

— Maria Brito, MD

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