The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC): A report of 2,781 cases in a Chinese population.

Yanli Zhu,Yuntao Song,Guohui Xu,Zhihui Fan,Wenhao Ren

doi:10.21147/j.issn.1000-9604.2020.02.02

Abstract

ObjectiveTo evaluate the diagnostic utility of The Bethesda System for Reporting Thyroid Cytology (TBSRTC) at Peking University Cancer Hospital, the incidence of noninvasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTP), and the impact of reclassification on cytopathological outcomes.MethodsWe performed a retrospective study of thyroid fine-needle aspiration (FNA) cases between April 2014 and March 2019. The FNA results were classified according to TBSRTC. Post-surgery histological findings were followed up.ResultsA total of 2,781 thyroid FNAs were performed. The incidences of the 6 diagnostic categories (DCs I−VI) were 14.8%, 17.1%, 15.8%, 2.3%, 11.6% and 38.5%, respectively. A total of 1,122 patients (40.3%) had corresponding histological results. NIFTP accounted for 0.4% of papillary thyroid carcinoma (PTC) cases, and there was no significant difference in the risk of malignancy (ROM) for each TBSRTC DC between “NIFTP=carcinoma (Ca)” and “NIFTP≠Ca”. When “NIFTP=Ca”, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of TBSRTC were 98.0%, 84.0%, 99.4%, 58.3%, and 97.5%, respectively. When “NIFTP≠Ca”, the sensitivity, specificity, PPV, NPV and accuracy of the TBSRTC were 98.1%, 81.5%, 99.3%, 61.1%, and 97.5%, respectively.ConclusionsTBSRTC is effective in the preoperative diagnosis of thyroid nodules in Peking University Cancer Hospital. The impact of the reclassification of NIFTP on cytopathological outcomes is limited because of its low incidence, and the revised ROMs are not suitable for Asian patients.

Highlights

Fine-needle aspiration (FNA) of the thyroid gland is a rapid, cost-effective, safe and widely accepted method in the preoperative evaluation of thyroid nodules
The The Bethesda System for Reporting Thyroid Cytology (TBSRTC) consists of 6 diagnostic categories (DCs), and each diagnostic category is associated with a specific risk of malignancy (ROM) and a recommendation for clinical management
The reclassification of NIFTP is of great significance for the cytological interpretation of thyroid nodules because the ROMs for TBSRTC DCs would decrease as reported in Western practice [3,4,5,6], and the revised 2015 American Thyroid Association (ATA) guidelines cites data from TBSRTC II [7]

Summary

Introduction

Fine-needle aspiration (FNA) of the thyroid gland is a rapid, cost-effective, safe and widely accepted method in the preoperative evaluation of thyroid nodules. The reclassification of NIFTP is of great significance for the cytological interpretation of thyroid nodules because the ROMs for TBSRTC DCs would decrease as reported in Western practice [3,4,5,6], and the revised 2015 American Thyroid Association (ATA) guidelines cites data from TBSRTC II [7]. Some Asian studies have shown high ROMs in the indeterminate FNA categories and low incidences of NIFTP in their thyroid FNA practice [8,9,10]. The incidences of NIFTP and the impact of reclassification on cytopathological outcomes remain unclear, and whether the revised ROMs are suitable for Asian patients remains to be further studied [8,11]

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Discussion

Conclusion