A. R. Marcadis1, B. Wang1, M. Rodriguez1, S. Liu1, J. I. Lew1 1University Of Miami,Division Of Endocrine Surgery,Miami, FL, USA
Introduction: Surgeon performed ultrasound (SUS) has been shown to be a valuable imaging modality in the preoperative prediction of malignancy or benignity of thyroid nodules. While patients with papillary thyroid cancer (PTC) are generally considered to have an excellent prognosis, there are some variants of PTC that exhibit more aggressive behavior and may constitute a worse prognosis. The purpose of this study is to determine if SUS can further predict not only malignancy in thyroid nodules, but also more aggressive variants of PTC.
Methods: A retrospective review of 1822 consecutive patients who underwent thyroidectomy at a single institution was performed. Only patients with final pathology confirming the presence of variant PTC and who underwent SUS prior to thyroidectomy were included (n=400). More aggressive variants of PTC were defined as diffuse sclerosing and tall cell variants, whereas classic and follicular variants of PTC were considered less aggressive. SUS characteristics of thyroid nodules were studied, including type (solid, mostly cystic, mixed), calcifications (micro-, coarse, none), borders (irregular, regular), shape (taller greater than wider), and echogenicity (hyper-, hypo-, isoechoic). SUS features were correlated with final histopathology using univariate regression analysis. For SUS features that are statistically significant (p<0.05), odds ratio (OR), confidence interval (CI), and p-values are presented.
Results: On final histopathology, 49 patients (12%) had more aggressive variants of PTC. On univariate analysis, hypoechogenicity (p<0.005, OR=2.700, CI [1.382-5.248]), microcalcifications (p<0.005, OR=2.389, CI [1.306-4.369]) and irregular border (p=0.043, OR=1.853, CI [1.014-3.387]) were SUS features that correlated significantly with more aggressive variants of PTC. Combining 2 of these features increased the predictive value of SUS for aggressive variants (hypoechogenicity and microcalcifications p<0.005, OR=5.757, CI [2.192-15.121]; hypoechogenicity and irregular border p<0.005, OR=3.810, CI [1.590-9.125]; irregular border and microcalcifications p<0.005, OR=2.787, CI [1.384-5.613]). The combination of all three SUS features of hypoechogenicity, microcalcifications, and irregular border had the strongest association for aggressive variants of PTC (p<0.005, OR = 7.054, CI [2.418-20.574]).
Conclusion: The combination of all three SUS features of hypoechogenicity, microcalcifications, and irregular border strongly predicts more aggressive variants of PTC with a 7-fold higher likelihood of being diffuse sclerosing or tall cell variants on final pathology. SUS, therefore, can potentially predict the biologic behavior of PTC at time of diagnosis, and help guide the surgeon in the operative and peri-operative management of these patients.