Preoperative Clinical and Ultrasonographic Predictors for Aggressive Behaviors in Sporadic Medullary Thyroid Carcinomas

Objective: To explore the clinical and ultrasonographic predictors for aggressive behaviors preoperatively in sporadic medullary thyroid carcinomas (MTCs). Materials and Methods: The preoperative clinical and ultrasonographic characteristics of patients diagnosed with MTCs between January 2009 and May 2022 were retrospectively reviewed. MTCs were described and categorized according to the American College of Radiology (ACR) thyroid imaging reporting and data system classification by 2 radiologists. Interobserver agreement was evaluated by kappa test. Univariate and multivariate analyses were performed to identify predictors of aggressive behaviors in MTCs. The log-rank test was utilized to compare differences in Kaplan-Meier (K-M) curves for postoperative disease-free survival (PDFS). Results: A total of 120 patients were enrolled in the final study. Male sex was significant risk factor for metastasis, perithyroidal invasion, and lateral cervical lymph node (LCLN) metastasis odds ratio (OR): 3.109, P = .019; OR: 5.316, P = .018; OR: 5.154 P = .012, respectively. The kappa values for all ultrasonic characteristics were high (ranged from 0.811 to 0.941). Size, focality, and margin of the nodule were independent risk factors for metastasis, as well as for LCLN metastasis. Whereas margin ( P < .001) and a subcapsular location ( P = .021) were risk factors for perithyroidal invasion. According to K-M analysis, PDFS of patients differed significantly between groups with/without metastasis ( P < .001), groups with/without perithyroidal extension ( P < .001) and groups with/without LCLN metastasis ( P < .001). Conclusions: Male sex is an independent risk factor for metastasis, perithyroidal invasion, and LCLN metastasis. The large size (≥2.55 cm for metastasis, ≥2.15 cm for LCLN metastasis, respectively), multifocality, and irregular margin of nodules were independent risk factors for both metastasis and LCLN metastasis. Extrathyroidal extension and a subcapsular location were risk factors for perithyroidal invasion. Moreover, patients with metastasis/perithyroidal extension/LCLN metastasis exhibited worse PDFS.