Repeat fine-needle aspiration cytology of benign thyroid nodules may be unnecessary
In a series of thyroid nodules from adults in Ireland, the false-negative rate of an initial benign thyroid fine-needle aspiration was low, around 1%, suggesting that routine second fine-needle aspiration biopsy may not be needed.
“This is real-life experience and reflects the practice in most thyroid centers,” Amar Agha, MD, a consultant endocrinologist in the department of endocrinology at Beaumont Hospital, Dublin, and colleagues wrote in study results published in BMC Endocrine Disorders.
According to the researchers, debate remains about whether radiologically or clinically defined low-risk thyroid nodules that meet the criteria for fine-needle aspiration (FNA) biopsy require repeat FNA when initial cytology is Thy 2, or benign.
“We previously reviewed our cohort of patients with benign reported thyroid nodules using routine repeat FNA biopsy and found a low risk of malignancy after first benign cytology,” the researchers wrote. “The primary aim of this study is to extend our previous study to investigate the malignancy rate of nodules classified as benign on initial FNA biopsy.”
In the present study, researchers retrospectively assessed 658 nodules from 653 patients (65.7% women; mean age, 53.2 years) from 2013 to 2017 in a tertiary referral institution. A radiologist with thyroid pathology expertise performed all FNA biopsies using ultrasound.
Researchers used U.K. Royal College of Pathologists guidelines to cytologically classify nodules while making decisions about further management at a regular thyroid multidisciplinary meeting. They decided follow-up of the Thy 2 nodules based on clinical and radiologic criteria.
Overall, researchers classified 76% of nodules as Thy 2 after the first FNA biopsy. Among modules initially classified as benign, 41.6% underwent repeat FNA, and 1.8% were surgically removed without repeat FNA; all others received clinical and or radiologic follow-up.
At follow‐up (mean, 74.5 months), researchers reported that 1.4% of nodules initially classified as Thy 2 were malignant or harboring malignancy. Papillary thyroid microcarcinomas were observed in two thyroid glands of benign nodules, which resulted in a true prevalence of 1%.
“With a well-targeted FNA biopsy, the false-negative rate of an initial benign thyroid FNA is very low, thus routine second FNA biopsy is not required in patients with a thyroid nodule initially deemed benign,” the researchers concluded. “Multidisciplinary input is imperative in informing decision-making.”
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