Correlation between Preoperative Ultrasonic Features of Medullary Thyroid Carcinoma and Postoperative Recurrence

Background: To investigate the factors that affect postoperative recurrence in medullary thyroid carcinoma (MTC) patients, including preoperative ultrasonic characteristics and other factors. Method: A retrospective analysis of seventy four MTC patients who underwent the first thyroid surgery from 2009 to 2018 and who had complete follow-up data was conducted. According to the follow-up results, these patients were divided into the recurrence group (17 cases) and non-recurrence group (57 cases). The preoperative ultrasound characteristics, preoperative and postoperative calcitonin levels, and general informations of the two groups were recorded, respectively. Univariate and multivariate analyses were performed. Results: Single factor Kaplan-Meier (K-M) analysis showed that: ① Preoperative ultrasonic characteristics including tumor size > 40.0 mm, capsular invasion, and metastatic cervical lymph nodes, as well as preoperative calcitonin level > 565.8 pg/ml, and postoperative calcitonin (within one week) level > 45.0 pg/ml were positively correlated with the risk of postoperative recurrence of MTC (P 0.05). Multivariate Cox regression analysis showed that metastatic lymph nodes shown by ultrasound (HR=5.368, 95%CI 1.063-27.104, P=0.042) was an independent risk factor for postoperative recurrence of MTC. Conclusions: MTC patients with metastatic lymph nodes shown by ultrasound are prone to postoperative recurrence of MTC. In addition, MTC patients with a tumor > 40.0 mm, capsular invasion, preoperative calcitonin level > 565.8 pg/ml, and postoperative calcitonin level > 45.0 pg/ml are more likely to have postoperative recurrence.