Retrospective cytological evaluation of indeterminate thyroid nodules according to the British Thyroid Association 2014 classification and comparison of clinical evaluation and outcomes

Abstract

The cytology of 130 indeterminate nodules (Thy 3) was retrospectively reviewed according to the British Thyroid Association 2014 classification. Nodules were divided into Thy 3a (atypical features) and Thy 3f (follicular lesion) categories. Histology was available as a reference for 97 nodules. Pre-surgical evaluations comprised biochemical tests, color-Doppler ultrasonography (US), semi-quantitative elastography-US (USE), contrast-enhanced US (CEUS), and mutation analysis from cytological slides. Thyroid malignancy was the final diagnosis for 19% of surgically-treated nodules. No statistically significant difference in the risk of malignancy was found between Thy 3a (26%) and Thy 3f (14%) nodules. Histology of the Thy 3a and Thy 3f nodules showed a higher incidence of Hurtle cell adenomas in Thy 3f (29%) than in Thy 3a (3%) nodules (P=0.01). The only pre-surgical difference concerned the BRAF V600E mutation, which was positive in some Thy 3a but not in any Thy 3f nodules (P=0.04). Receiver-operating characteristic (ROC) analysis was used to obtain cut-off values from US (score), USE (ELX 2/1 strain index), and CEUS (time-topeak index and peak index) data. The cut-off values were similar for Thy 3a and Thy 3f nodules. Data showed that malignancy can be suspected if the US score is >2, ELX 1/2 strain index >1, time-to-peak index >1, and peak index <1. In a sub-group of 24 revised nodules (12 Thy 3a and 12 Thy 3f) with histology as a reference, the diagnostic power of cumulative pre-surgical analysis by means of US, USE, and CEUS showed high positive and negative predictive values (83% and 100%, respectively) for the presence of malignancy in Thy 3a and Thy 3f nodules. In conclusion, in our series of revised Thy 3 nodules, malignancy was low and displayed no significant differences between Thy 3a and Thy 3f categories. The use of cut-offs based on histology as a reference could reduce surgery. Our data support the conviction that, in mutation-negative Thy 3a and Thy 3f nodules, observation should be the first choice when not all instrumental results are suspect.

中文概要

题目

甲状腺不确定结节的回顾性细胞学评估研究

目的

回顾性分析了130 例甲状腺不确定结节的临床评估和预后,以及组织细胞学检测结果,为甲状腺结节的治疗提供合理的治疗方法。

方法

根据英国甲状腺协会2014 年分类,回顾性分析了2011 年1 月至2014 年12 月130 例甲状腺不确定结节(Thy 3)的细胞学检查。将结节分为Thy 3a(非典型特征)和Thy 3f(滤泡病变)两类。比较评估术前生物化学检查、彩色多普勒超声检查(US)、半定量弹性超声成像(USE)、超声造影(CEUS)、细胞学、组织学以及分子生物学突变分析等结果。

结论

Thy 3 结节的恶性肿瘤发生率较低,且在Thy 3a和Thy 3f 之间没有显著差异。使用基于组织学的截取值作为参考可以降低采用手术的治疗方案。在阴性突变的Thy 3a 和Thy 3f 结节中,当不是所有的仪器检测结果都疑是阳性时,组织学观察应该作为首选。