A majority of asymptomatic, benign thyroid nodules had no significant change in size after 5 years of follow-up, according to study findings published in JAMA.
Thyroid cancer diagnoses were rare, the researchers wrote.
Sebastiano Filetti, MD, of the Universitá di Roma Sapienza in Rome, and colleagues evaluated data on 992 patients with one to four asymptomatic, sonographically or cytologically benign thyroid nodules from a prospective, multicenter, observational study to determine the frequency, magnitude and factors associated with changes in nodule size. Patients were followed for 5 years.
The size of nodules remained stable in 69% of the patients, whereas they shrank in 18.5% and grew in 15.4% of patients. Of the 1,567 original nodules measured, 11.1% increased in size. The presence of multiple nodules was associated with nodule growth.
A benign diagnosis at baseline was confirmed in 98.9% of 365 patients whose nodules were reaspirated. Fine-needle aspiration was repeated at the 5-year follow-up in 245 of these patients to confirm the baseline diagnosis.
Overall, five cases of thyroid cancer were found in the original 1,567 nodules.
“Among patients with asymptomatic thyroid nodules that were sonographically or cytologically benign, the majority of nodules exhibited no significant size change during 5 years of follow-up or they actually decreased in size,” the researchers wrote. “Significant nodule growth occurred in 15% of cases, new nodules developed in 9.3% of patients, and thyroid cancer was diagnosed in 0.3% of nodules. These findings justify recommendations for follow-up of asymptomatic thyroid nodules.”
In an accompanying editorial, Anne R. Cappola, MD, ScM, and Susan J. Mandel, MD, MPH, of the Perelman School of Medicine at the University of Pennsylvania in Philadelphia, wrote that the study has four important implications for the follow-up of thyroid nodules, including reassurance of validity of benign cytology results that are obtained by ultrasound-guided fine-needle aspiration and also confirmation of a low false-negative rate; evidence that routine sonographic surveillance for growth with fine-needle aspiration is not the most effective method for detecting small numbers of missed cancers; verification that many nodules detected by ultrasound are small and not suspicious; and demonstration that increase in size is not a predictor of malignancy.
“Thyroid nodules are pervasive, whereas thyroid cancer is not,” the researchers wrote. “The findings from Durante et al represent an important step in improving the efficiency and mitigating the expense of follow-up for the vast majority of thyroid nodules that are either cytologically or sonographically benign.” – by Amber Cox
Disclosure: The researchers report no relevant financial disclosures.