83rd Annual Meeting of the American Thyroid Association:
US-FNA with Molecular Diagnostic Testing: What did the study reveal?
Thyroid cancer is found in 5-15% of palpable thyroid nodules—it is the most common type of endocrine malignancy. Fine needle aspiration (FNA) performed using ultrasound (US) guidance is the standard pre-operative diagnostic procedure. However, 15-30% of FNA cytological results are indeterminant leading the clinician to question," is the nodule benign or malignant?" Many of those patients are referred for diagnostic thyroid surgery (hemithyroidectomy), and the majority of indeterminant nodules are benign.
Molecular testing in conjunction with FNA was one of the topics presented during the American Thyroid Association's annual meeting. Researchers conducted a case control study to better understand molecular testing in several hundred pre- and post-surgical thyroid specimens.
About the Case Control Study
Considering benign and malignant thyroid tumors, the two-fold goal of the case control study was to (1) better understand "the distribution and frequency of clinically relevant oncogenic gene mutations," and (2) develop a diagnostic methodology.
- US-FNA pre-operative thyroid specimens (n=250)
- Surgically resected thyroid lesions (n=54)
- Both groups (n=304) were evaluated for alterations in the BRAF, HRAS, KRAS, NRAS, PAX8 and RET genes using the miRInform® Thyroid Panel (Asuragen, Austin, TX)
- miRNA expression analyses were performed alongside RT-PCR (reverse transcription polymerase chain reaction)
Histology of both groups resulted in 113 benign and 191 malignant tumors. Cross-validation (n=254) and validation experiments showed increases in thyroid cancer detection, as follows:
- Genotyping alone: 59-63%
- Genotyping and miRNA: 75-85%