How to use molecular testing results to guide surgery: a surgeon's perspective.

Area of Science:

• Oncology
• Genetics
• Endocrinology

Background:

• Thyroid cancer diagnosis involves cytologic analysis of fine-needle aspiration (FNA) specimens.
• Genetic mutations are linked to thyroid cancer development and progression.
• Molecular testing of FNA is emerging as a tool to complement cytologic diagnosis.

Purpose of the Study:

• To review the utility of molecular testing of FNA specimens in guiding surgical decisions for thyroid cancer.
• To examine how molecular data can inform the management of thyroid nodules.

Main Methods:

• Review of meta-analyses on B-type RAF kinase mutations in papillary thyroid cancer.
• Evaluation of gene mutation panels and gene-expression classifiers for FNA specimens.
• Analysis of data regarding specificity, positive predictive value, sensitivity, and negative predictive value.

Main Results:

• B-type RAF kinase mutations correlate with advanced thyroid cancer features like extrathyroidal extension and lymph node metastases.
• Gene mutation panels show high specificity and positive predictive value for malignancy.
• Gene-expression classifiers demonstrate high sensitivity and negative predictive value in indeterminate FNAs.
• These molecular tests are influencing clinical practice despite a lack of consensus.

Conclusions:

• Molecular testing of FNA specimens can help avoid diagnostic thyroidectomy.
• It can also assist in determining the appropriate extent of surgery for patients with indeterminate FNA results.
• The American Thyroid Association is currently reviewing the use of these molecular tests.