CALCA and medullary thyroid gland carcinoma: In this study, the results of univariate KM analysis showed that: tumor size > 40.0 mm, capsular invasion, metastatic cervical lymph nodes, preoperative calcitonin > 565.8 pg/ml, and postoperative calcitonin > 45.0 pg/ml were risk factors for MTC recurrence (P < 0.05).