METHODS
A retrospective multicenter cohort study of patients who underwent
thyroid surgery at two tertiary care academic hospitals from January 1,
2016 to December 1, 2019 was performed. Consecutive patients with a
dominant thyroid nodule who underwent both USFNA and molecular profile
testing (ThyGeNEXT, Interpace Diagnostics, Parsippany, NJ, USA or
ThyroSeq v3, UPMC, Pittsburgh, PA, USA) followed by thyroidectomy were
included in the study. Indications
for molecular profile testing of thyroid nodules was for cytologically
indeterminate Bethesda category (III, IV, V) or discordance cytology
results with ultrasound findings. Patients who did not undergo
thyroidectomy as well as pediatric patients were excluded from the
study. This study was approved by the Research Ethics Committee at the
tertiary care center (REB 2019-1532).
Clinical data including age, sex, Bethesda category of the dominant
nodule, and if a molecular mutation was identified were collected. In
addition, the extent of thyroidectomy performed (hemi, total or
completion thyroidectomy) and postoperative histopathology were noted.
Postoperative histopathology was classified as benign disease, malignant
or non-invasive follicular thyroid neoplasm with papillary-like nuclear
features (NIFTP). Furthermore, PTC of less than 10mm were classified as
microcarcinomas. Additionally, aggressive thyroid cancer was defined as
any evidence of thyroid carcinoma variants (tall cell, hobnail, solid,
diffuse sclerosing, anaplastic or poorly differentiated), clinical
evidence of extrathyroidal extension or central neck metastasis.
The STROBE guidelines were used for reporting data. Descriptive
statistics to characterize the cohort was performed. The association
between Bethesda category and type of molecular mutation of dominant
thyroid nodule on USFNA was compared using Chi-square testing. Logistic
regression was performed to quantify the measure of association between
Bethesda category and type of molecular mutation of the dominant thyroid
nodule. Also, comparison of Bethesda category and molecular mutation to
postoperative pathology was performed using Chi-square testing.