Role of NGS-based ThyroSeq Panel in Cancer Diagnosis in Thyroid Nodules

Thyroid cancer is the fifth most common cancer type in women and the fastest growing cancer
diagnosis in the U.S. In 2013, an estimated 60,000 new cases were diagnosed. However, thyroid
nodules are much more common, particularly in woman and with increased age. The prevalence of
palpable nodules in population-based studies is 3-4% and the prevalence of non-palpable
nodules incidentally identified on imaging approaches 40-50% after the age of 60. Thyroid
cancer is the primary clinical concern in patient with thyroid nodules, although only small
proportion (~5%) of thyroid nodules is malignant . The diagnosis of thyroid cancer relies on
cervical ultrasound and fine needle aspiration (FNA) biopsy with cytologic examination. FNA
cytology provides a definitive diagnosis of benign or malignant thyroid disease in most
cases, although in approximately 30% of nodules, FNA cytology cannot reliably rule out cancer
and such cases are reported as indeterminate for malignancy. Because of the lack of a
definitive diagnosis, most patients with indeterminate cytology undergo diagnostic surgery to
establish histopathologic diagnosis. However, only 20-30% of such surgically resected thyroid
nodules will prove to be malignant. It has been estimated that ~150,000 thyroid surgeries are
performed in the U.S. for benign nodules due to inability to rule out cancer without surgery.
Additionally, an indeterminate preoperative diagnosis does not always lead to the optimal
initial surgical intervention for patients who have thyroid cancer, as many of them undergo a
two-step surgery, i.e. thyroid lobectomy followed by completion total thyroidectomy. Both
unnecessary and two-step surgeries can be avoided with a more accurate preoperative diagnosis
of cancer in thyroid nodules.

For patients who have signed an informed consent, the physician investigator will then
perform a research needle wash. The syringe will be rinsed with a buffer solution to gather
left over cells for the research sample. This FNA material will be collected for potential
molecular testing into a collection tube that is stored at -20C.

The first five samples acquired will be processed irrespective of cytologic diagnosis to
evaluate the collection technique.

Those samples that have indeterminate cytologic diagnosis (Bethesda III, VI, or V) and
surgical outcome are submitted for molecular testing. (Sample will be given a code that
de-identifies the sample before it is sent to the testing laboratory. The lab that will
analyze specimens is a CLIA certified Pitt lab.)

Molecular analysis is performed at the Pitt lab without knowing surgical outcome.

Inclusion Criteria:

- Patients that undergo a clinically diagnostic thyroid FNA

Exclusion Criteria:

- Children

- pregnant women