Endocrine Abstracts

The evaluation of a thyroid nodule is a very common clinical problem and fine needle aspiration biopsy (FNAB) is the only test that can provide a definitive preoperative diagnosis of malignancy. The sensitivity and specificity of FNAB are limited by aspirates that yield insufficient material for definitive diagnosis and those with indeterminate diagnoses, which can account for up to 30–40% of all specimens. The detection of several novel gene mutations in differentiated thyroid cancer (DTC) over the last decade has led to the diagnostic use of these oncogenic alterations to improve FNAB sensitivity and specificity. In recent years, several prospective and retrospective studies have shown that molecular testing of thyroid nodules for a panel of mutations can be effectively performed in a clinical setting and can be useful to improve the diagnosis of malignancy when used as an adjunct to traditional cytology. In particular, either BRaf or ret/PTC, or PAX8/PPARg or ras, alone or as a panel of oncogenes, have been analyzed in FNA specimens by different Authors. Due to the reported association between BRaf and poorer prognosis, the diagnosis of a BRaf positive nodule can help both to diagnose and to identify those PTC patients who may need more aggressive surgical treatment and vigilant clinical monitoring. Cost/benefit studies showed that molecular testing of indeterminate FNAB results is cost saving predominantly because of reduction in two-stage thyroidectomy and can potentially avoid almost three fourths of currently performed surgeries in patients with benign nodules. In conclusion, the clinical application of molecular techniques to detect mutations in thyroid FNAB samples has been shown to improve the preoperative diagnosis for DTCs and is particularly useful for those tumors that are ‘indeterminate’ by traditional cytological analysis.