Arch. Endocrinol. Metab. 2020;64(4):329-330
The run for a million continues: is there still space for traditional techniques beyond molecular testing for indeterminate thyroid nodule cytology?
DOI: 10.20945/2359-3997000000277
Thyroid nodules are increasingly common in our daily lives and the duo “thyroid ultrasound (US) & fine needle aspiration biopsy (FNAB)” remains the gold standard for identifying or ruling out malignancy with high accuracy ( ). However, we know that out of these nodules, about 25% has an undefined cytology, being named “indeterminate samples” or, according to the Bethesda’s Classification System, categories III (atypia of undetermined significance – AUS/follicular lesion of undetermined significance – FLUS) and IV (follicular neoplasm – FN/suspicious for follicular neoplasm – SFN) ( ). About 10 years ago, the standard management for these two categories, had been a diagnostic lobectomy ( ). In this way, in order to minimize the number of unnecessary surgeries, the “run for a million” had its start decreed, and many groups started to run after tools that would reduce the number of indeterminate cytology and thus differentiate benign from malignant samples before a surgical procedure becomes really necessary.
The use of frozen section was one of the first solutions to deal with the nodules with indeterminate cytology ( ). The intention was to define intraoperatively if the surgery could be limited to a lobectomy or if total thyroidectomy or even neck dissection was needed. Real-time elastography appeared in the race when the role of some US criteria, through the use of the ACR-TIRADS classification ( ), gained more evidence in the definition of benignity or malignancy of a nodule. Also others diagnostic images as thyroid scintigraphy, in which the capturing nodule could suggest benignity ( ), were suggested as possible candidates. In addition, immunocytochemistry entered this race by using CITED-1, galectin-3, HBME-1, fibronectin-1 and cytokeratin-19 as possible markers ( ). Nevertheless, the molecular markers are the ones which intensified the contest in the beginning of the 90s and which apparently are gaining more and more advantage over the others ( ).
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