TI‑RADS guides repeat FNA

A thyroid biopsy can come back “nondiagnostic,” meaning the needle pulled too few cells to tell whether a nodule is benign or cancerous. A new Cancer Cytopathology study says ultrasound risk scoring may help decide which of those nodules need another biopsy. (booksci.cn) The study looked at 139 thyroid nodules with Bethesda category I, also called B1, the standard label for a nondiagnostic biopsy result. All 139 later had a repeat biopsy or surgery that gave a final diagnosis. (booksci.cn) Researchers then matched each nodule to the American College of Radiology Thyroid Imaging Reporting and Data System, or ACR TI-RADS, which sorts ultrasound findings into higher- and lower-risk groups. Of the 139 nodules, 11 were malignant, for an overall cancer rate of 7.9%. (booksci.cn) Cancer risk was 0% in TI-RADS 1 and 2 nodules, 2.9% in TI-RADS 3, 5.9% in TI-RADS 4, and 46.2% in TI-RADS 5. The study found 5 TI-RADS points was the best cutoff for predicting malignancy. (booksci.cn) The authors concluded that B1 nodules in TI-RADS categories 1 through 3 may not need repeat fine-needle aspiration. They said repeat biopsy should still be considered for TI-RADS 4 and 5 nodules, where ultrasound showed more suspicious features. (booksci.cn) That question matters because thyroid nodules are common, and most are not cancer. The American College of Radiology says TI-RADS was built to standardize ultrasound reporting and reduce unnecessary biopsies of nodules that ultimately prove benign. (acr.org) Nondiagnostic biopsies are common enough to shape day-to-day care. The American Thyroid Association says they occur in 5% to 10% of biopsies, and older guideline-based practice has often led to repeating the biopsy after that result. (thyroid.org) Recent research has pushed in the same direction, though not with the same exact tool. A 2024 review in Endocrine Practice said operator experience, nodule depth, and cystic content are among the more consistent factors linked to nondiagnostic samples, suggesting some repeat procedures fail for technical reasons rather than because the nodule is dangerous. (pubmed.ncbi.nlm.nih.gov) Another recent series in Diagnostic Cytopathology found 55 repeat biopsies after nondiagnostic thyroid aspiration produced abnormalities in 5 cases, with no primary thyroid cancers identified on follow-up. The authors said ultrasound and clinical follow-up may be more appropriate than automatic repeat biopsy for many patients. (pubmed.ncbi.nlm.nih.gov) The new study does not replace clinical judgment, and its 139-nodule sample was retrospective. But it gives clinicians a simple rule already used in thyroid ultrasound: if the first biopsy is nondiagnostic, the scan may help show who can wait and who should go back for another needle. (booksci.cn)