Predictive value of ultrasonic features and microscopic extrathyroidal extension in the recurrence of PTC

Abstract

Purpose: To determine the clinical value of ultrasonic features, especially extrathyroidal extension (ETE), in the prediction of PTC recurrence.

Method: A total of 863 patients with PTC confirmed by pathological examinations from January 2012 to August 2018 were selected in this study, including 59 cases of recurrence. The Cox-proportional hazards regression analysis and Kaplan-Meier method were adopted to determine the relationship between the variables and recurrence free survival (RFS).

Results: The recurrence rate of PTC is 6.8 %. Tumor maximum diameter, margin, multifocality, microcalcifications, ETE and preoperative lymph node metastasis were valuable predictive factors in univariate survival analysis. Tumor larger than 20 mm, multifocality and lateral cervical lymph node metastasis were independent risk factors for PTC recurrence, and lymph node metastasis has the highest hazard ratio (HR). Preoperative lateral cervical lymph node metastasis was more often found in the gross and extensive ETE groups. Microscopic ETE has little value in predicting PTC recurrence and has no correlation with preoperative cervical lymph node metastasis.

Conclusions: Tumor maximum diameter >20 mm, multifocality and lateral cervical lymph node metastasis were independent risk factors for PTC recurrence. Preoperative lateral cervical lymph nodes should be carefully examined when gross ETE and extensive ETE were detected. Microscopic ETE has no impact on preoperative cervical lymph node metastasis or tumor recurrence.

Keywords: Microscopic ETE; PTC; Recurrence; Ultrasonic features.