Timing of repeat thyroid fine-needle aspiration in the management of thyroid nodules

The Bethesda System for reporting thyroid fine-needle aspirations (FNAs) recommends repeat aspirations be done at least 3 months following the initial aspiration to prevent false-positive misinterpretations due to reactive/reparative changes. Because limited data exists, we reviewed our own data to ascertain the recommendation.

We retrospectively reviewed thyroid FNAs accessioned in the Cytology Laboratory at Beth Israel Deaconess Medical Center in Boston, Mass., USA, from January 2006 to December 2008. We identified patients with repeat aspirates of a single lesion and those with thyroidectomy specimens. Cytologic and surgical diagnoses along with time between FNAs were recorded.

No statistically significant difference was detected in the distribution among nondiagnostic, suboptimal, and adequate categories with respect to the timing of repeat FNA (p = 0.25). Forty-six percent of the lesions that were nondiagnostic/suboptimal initially yielded the same results on repeat. Twenty-eight percent of initially adequate specimens were nondiagnostic/suboptimal on repeat (p = 0.04). Nine percent of those with an initial atypical diagnosis had the same diagnosis on repeat, while 2.6% of those who did not have an initial atypical diagnosis had an atypical diagnosis on repeat (p = 0.29). False positives between early (16%) and late (12%) repeats were not statistically significant (p = 0.74).

The diagnostic yield and accuracy of repeat FNA is independent of the time interval between procedures but may be related to the original FNA diagnosis.