Background Extrathyroidal extension (ETE) significantly affects the treatment strategy for thyroid cancer. We present a new method to predict ETE of papillary thyroid carcinoma (PTC). methods We enrolled 1 481 patients with PTCs. The ETE was classified into minimal and gross ETE. Using the novel "contact angle of the tumor on sonography" (CATS) system, we calculated optimal cutoffs for predicting ETE according to tumor location and compared the diagnostic performance to that of previous methods. Results The optimal cutoff angles for predicting anterior minimal and gross ETE were 41.5° and 49.4°, respectively, while those for posterior ETE were 39.8° and 54.6°, respectively. The optimal cutoff angle predicting tracheal ETE was 88.0°. The diagnostic performance was comparable to that of previous methods. Conclusion The CATS method for predicting ETE is a valuable alternative.

中文翻译：

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超声检查系统上肿瘤接触角的最佳截止值，通过肿瘤位置预测甲状腺乳头状癌的甲状腺外扩展。

背景 甲状腺外扩展（ETE）显着影响甲状腺癌的治疗策略。我们提出了一种预测甲状腺乳头状癌 (PTC) ETE 的新方法。方法 我们纳入了 1 481 名 PTC 患者。ETE 分为最小 ETE 和总 ETE。使用新型“超声检查肿瘤接触角”(CATS) 系统，我们根据肿瘤位置计算了预测 ETE 的最佳截止值，并将诊断性能与之前的方法进行了比较。结果预测前部最小ETE和总ETE的最佳截止角分别为41.5°和49.4°，而后部ETE的最佳截止角分别为39.8°和54.6°。预测气管ETE的最佳截止角为88.0°。诊断性能与以前的方法相当。结论 CATS 预测 ETE 方法是一种有价值的替代方法。