Endocrine Abstracts

Background: Extrathyroidal extension (ETE) is an important factor to determine treatment strategy of thyroid cancer. The purpose of this study was to present a new method to predict ETE in papillary thyroid carcinoma (PTC).

Methods: This study included 1,481 patients with PTCs. The ETE was classified into minimal and gross ETE. Using an protrusion angle of the tumor on sonography (PATOS) system, we calculated optimal cut-off values to predict ETE according to tumor location. And we compared diagnostic performance with previous ETE predicting methods.

Result: The optimal cut-off value to predict anterior ETE was 41.5° and 49.4°, minimal and gross ETE, prospectively. The optimal angle to predict posterior ETE was 39.8° and 54.6°, minimal and gross ETE, each. And the optimal cut-off value to predict tracheal ETE was 88.0° by the PATOS system. The diagnostic performance showed competitive results with previous methods.

Conclusions: The new method for predicting ETE proposed in this study which is PATOS system could be an alternative method.