Current Status of Thyroid Fine-Needle Aspiration Practice in Thailand

The Asian Thyroid Working Group, from 2017 to 2023

The Asian Thyroid Working Group was founded in 2017 at the 12th Asia Oceania Thyroid Association (AOTA) Congress in Busan, Korea. This group activity aims to characterize Asian thyroid nodule practice and establish strict diagnostic criteria for thyroid carcinomas, a reporting system for thyroid fine needle aspiration cytology without the aid of gene panel tests, and new clinical guidelines appropriate to conservative Asian thyroid nodule practice based on scientific evidence obtained from Asian patient cohorts. Asian thyroid nodule practice is usually designed for patient-centered clinical practice, which is based on the Hippocratic Oath, "First do not harm patients," and an oriental filial piety "Do not harm one's own body because it is a precious gift from parents," which is remote from defensive medical practice in the West where physicians, including pathologists, suffer from severe malpractice climate. Furthermore, Asian practice emphasizes the importance of resource management in navigating the overdiagnosis of low-risk thyroid carcinomas. This article summarizes the Asian Thyroid Working Group activities in the past 7 years, from 2017 to 2023, highlighting the diversity of thyroid nodule practice between Asia and the West and the background reasons why Asian clinicians and pathologists modified Western systems significantly.

Application of the Bethesda system for reporting thyroid cytopathology for classification of thyroid nodules: A clinical and cytopathological characteristics in Bhutanese population

INTRODUCTION

The existence of baseline data on the spectrum of thyroid nodules in Bhutanese patients is unknown. Fine-needle aspiration cytology (FNAC) is regarded as the gold standard diagnostic test for pre-op assessment of thyroid lesions.

MATERIALS AND METHODS

We conducted a retrospective study, involving 765 patients who underwent FNAC of the thyroid gland, at Jigme Dorji Wangchuck National Referral Hospital, Thimphu, between January-2018 to December-2020. We aimed to assess the cytomorphological spectrum of thyroid nodules, classify them as per The Bethesda system for reporting thyroid cytopathology (TBSRTC), assess risk of malignancy (ROM), and evaluate the accuracy of FNAC in diagnosing thyroid malignancy.

RESULTS

Colloid nodule (37.4%) and papillary thyroid carcinoma (4.2%) constituted the majority of benign and malignant cytological diagnoses, respectively. According to TBSRTC, majority of the cases (82.0%) fell under the Bethesda II category. Bethesda III was the least common (1.4%) category. As compared to histopathological diagnosis; the sensitivity, specificity, positive and the negative predictive values of FNAC in diagnosing thyroid malignancy were 90.0%, 93.3%, 93.10%, and 90.32% respectively. The ROM increased concurrently with the grade of the Bethesda category and was more or less close to the ROM reference range, published in the TBSRTC.

CONCLUSION

Benign thyroid nodules (82.0%) constituted a majority of thyroid nodules in Bhutanese patients. FNAC was found to be reliable in detecting thyroid malignancy. From the literature, TBSRTC was found to be a more convenient method for reporting thyroid cytology. Henceforth, as most institutes, we plan to implement TBSRTC for reporting thyroid cytopathology.

Patient Discomfort in Relation to Thyroid Nodule Fine-Needle Aspiration (FNA) Performed with or without Parenteral and/or Topical Anesthetic

OBJECTIVE

There is much reported variation in the impact of local anesthesia on thyroid fine-needle aspiration (FNA) related discomfort. We compare patients undergoing thyroid FNA with subcutaneous injection or topical anesthetic to no anesthetic.

METHODS

We conducted a retrospective review of 585 sequential ultrasound guided thyroid FNA procedures in Mayo Clinic. Group 1 (n = 200), no anesthetic; Group 2 (n = 185), subcutaneous injection anesthetic; and Group 3 (n = 200), topical anesthetic. Patient demographics, number of FNA passes, needle gauge, and cytopathology were recorded plus a discomfort score (0 to 10) before and immediately post procedure in all 3 groups and peak discomfort during the FNA in Groups 1 and 2.

RESULTS

There were no differences among the 3 groups in age, sex, FNA sufficiency rate, cytopathology, and FNA passes number. There was no significant difference between Groups 1 and 2 in peak discomfort score during the FNA: 0 (45%, 42.2%), 1 to 2 (19%, 24.9%), 3 to 5 (23.5%, 20.5%), 6 to 8 (9.5%, 10.8%), 9 to 10 (3%, 1.6%), respectively. Discomfort score post procedure: 0 (78.5%, 77.8%, 53.5%), 1 to 2 (13%, 13%, 36.5%), 3 to 5 (7%, 7%, 9%), 6 to 8 (1.5%, 2.2%, 1%), 9 to 10 (0%, 0%, 0%) for groups 1, 2, and 3, respectively. There were no significant differences among the 3 groups for a discomfort score ≥3.

CONCLUSION

FNA associated patient discomfort was comparable during and after the procedure regardless of the use of anesthetic or the type utilized. Approximately 90% of patients experienced mild to moderate discomfort during the procedure. And 90% reported no more than a level 2 discomfort post procedure.

ABBREVIATIONS

End = endocrinology; FNA = fine-needle aspiration; MCF = Mayo Clinic Florida; MCR = Mayo Clinic Rochester.

Pathological practice and management of thyroid nodules: a Thai perspective

Although, in the thyroid field, there have been several internationally standard diagnostic and management guidelines for practitioners from every country to follow but there is still variation among physicians across the globe in taking care of patients and pathology specimens with thyroid nodules due to dissimilar backgrounds of each place. Thailand is one among several countries that tries to maintain standard of care to meet international requirements although, with some limitations, not all recommendations are followed. To understand how approaches of thyroid nodules are performed throughout the country and how the healthcare system of the whole kingdom is managed including what major current limitations, the authors conducted a survey among physicians consisting of surgeons, radiologists and pathologists who are involved in the management of the thyroid lesions by personal phone contact and custom online questionnaires. Performances of fine needle aspiration of different institutes are also evaluated by analyzing the data from available publications and compared their results with other series from the literature. Shortage of pathologists and un-equal resource allocation are the major problems concerning administrative aspect while a lack of awareness in new terminologies or diagnostic systems (e.g., NIFTP, UMP, Bethesda, TI-RADS) among physicians, particularly clinicians, are the problems of training and continuous medical education. Another point of concern is a rather poor performance in fine needle aspiration from the Thai series in which there are high rate (30.5%) of non-diagnostic category (Bethesda I) and false negativity as demonstrated by relatively high risk of malignancy (9.6%) in Bethesda II compared with other series from the literature. Regarding molecular studies, despite their usefulness in improving diagnostic accuracy, especially for cytology specimens, these ancillary tools are not routinely used in our practice since they are available in only few referral centers. This review provided a background information of the perspective on how thyroid nodules are managed in the Thai settings.

An overview of thyroid fine-needle aspiration practice in Myanmar

Fine-needle aspiration cytology (FNAC) of the thyroid is a widely accepted method for aiding the diagnosis of thyroid nodules. In Myanmar, it has been done since the early 1990s, and mainly performed by surgeons and otorhinolaryngologists. The interpretation of cytology is solely made by pathologists. Although some of the experts particularly those from specialist hospitals use the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC), many still prefer the British five-tier cytopathology report. Available local publications addressing the accuracy of FNAC and cytologic-histologic correlations were queried. Ten studies performed in 1991-2018 on 540 thyroid nodules were included. Cytologic-histologic correlations showed a range of sensitivity from 64.29% to 100%, specificity from 93% to 100%, and diagnostic accuracy from 94% to 100%. The adoption of TBSRTC by pathologists is still slow and should be encouraged via seminars and training programs. Further multihospital-based large cohort studies with uniform design and adequate follow-up are needed to better promote and assess utility of thyroid FNAC in Myanmar.

The diversities in thyroid cytopathology practices among Asian countries using the Bethesda system for reporting thyroid cytopathology

Background

The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) has been adopted and widely used among Asian countries. This study aims to investigate the application of TBSRTC in thyroid cytology practice among Asian countries.

Methods

We searched electronic databases including PubMed and Web of Science from 2010 to 2019. Meta-analysis of proportion and their 95% confidence intervals (CIs) were calculated using the random-effect model. Meta-regression and subgroup analysis were used to search for heterogeneity origins.

Results

We included 42 Asian studies with 84.953 fine-needle aspirations. Among six categories, benign was the most commonly diagnosed category. The resection rate (RR) and risk of malignancy (ROM) were highest in malignant and SM categories, and lowest among benign nodules. Thyroid cytology practice in Asia was characterized by a low RR and high ROM in patients with indeterminate thyroid nodules. There was a significant amount of heterogeneities of TBSRTC outputs (frequency, resection rate, and malignancy risk) among Asian countries. Meta-regression showed that the sources of heterogeneity might stem from the differences in study origin and the application of molecular testing. We highlighted the usefulness of preoperative molecular testing to select patients for surgery.

Conclusions

Our study provided insight regarding thyroid cytology practice among Asian countries. Active surveillance is commonly used in Asian practice resulting in a low RR and high ROM for indeterminate nodules. There are still variations in general thyroid cytology practice in Asia. Future guidelines and consensus regarding the application of TBSRTC in thyroid cytology practice among Asian countries are required.

Atypia of undetermined significance/follicular lesion of undetermined significance: Asian vs. non-Asian practice, and the Singapore experience

The Bethesda System for Reporting Thyroid Cytopathology has paved the way for comparisons of the practice of thyroid cytology in many different regions. However, there have been comparatively few studies documenting differences between Asian and non-Asian practice. Here, we aim to compare a few key parameters between the two regions, focusing on the indeterminate category of atypia of undetermined significance (AUS)/follicular lesion of undetermined significance (FLUS). We compared its incidence, resection rates (RRs), risk of malignancy (ROM), rate of repeat fine needle aspiration (rFNA), ROMs of cytomorphologic subcategories of nuclear atypia (AUS-N) vs. architectural atypia (AUS-A), and, finally, the incidence of papillary thyroid carcinoma (PTC) vs. follicular neoplasms (FNs) in resected AUS/FLUS cases in Asian and non-Asian regions. Where possible, these metrics were compared with the Singapore experience from a tertiary referral institution. While the incidence of AUS/FLUS was similar in both regions, we found geographical differences in the RRs and ROMs, which may reflect a higher collective threshold for surgery in Asian countries. However, both cohorts showed higher ROMs in the AUS-N subcategory as compared to the AUS-A subcategory, supporting the subclassification of the AUS/FLUS based on the presence of nuclear atypia. We also observed a higher incidence of AUS-N coupled with a higher incidence of PTC in resected AUS/FLUS nodules in Asian cohorts, while AUS-A and follicular-patterned neoplasms featured more prominently in the non-Asian cohorts. These incidences may account for the starkly different molecular approaches that we noted-in Asian (chiefly Korean and Chinese) centers, BRAF mutational analysis was favored, while gene panels and gene expression classifiers were more frequently applied in non-Asian centers (chiefly in the United States of America). Overall, the data from Singapore appears more closely aligned to non-Asian trends, despite its geographical location in Southeast Asia and its predominantly Asian population. We conclude that there is significant heterogeneity in the outcomes of the AUS/FLUS categories between and within regions, which is only partially explained by regional variations, and may also reflect different regional diagnostic and management practices. This highlights the importance of understanding the local context in the interpretation of indeterminate Bethesda categories, rather than adopting a "one-size fits all" approach.

Incidence and malignancy rates classified by The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) - An 8-year tertiary center experience in Thailand

Incidence and Malignancy Rates Classified by The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) – An 8-year Tertiary Center experience in Thailand.

Background

Fine-needle aspiration (FNA) of the thyroid is considered the best diagnostic tool for preoperative evaluation of thyroid nodules. The introduction of The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) in 2010 provided the opportunity to establish worldwide standard for reporting and terminology guidelines for diagnostic categories. It is recommended that every institution evaluates the risk of malignancy (ROM) in each category for quality improvement process.

Aim

To assess the effectiveness of TBSRTC method at our institution using cyto-histological correlation.

Method

A retrospective 8-year (2010–2017) audit of thyroid FNA done by thyroid specialists at Theptarin hospital. The FNA results were classified according to TBSRTC. Histopathology reports for operated cases were used to correlate cytology and final histopathology.

Results

A total of 2735 thyroid FNA from 2115 patients (mean age 45.7 ± 13.1 years, female 89.8%) were examined. The rates of non-diagnostic, benign, atypia of undetermined significance (AUS), follicular neoplasm, suspected for malignancy, and malignant cases were 21.1%, 66.6%, 4.7%, 2.4%, 1.8%, and 3.3% respectively. There were 188 patients (9%) who underwent surgical resection with available histopathology. Malignancy rates in operated thyroid nodules were 20.0%, 4.2%, 9.4%, 23.5%, 57.1%, and 90.3% for categories 1 to 6, respectively. The sensitivity, specificity, negative predictive value, and positive predictive value were 96.6%, 88.5%, 95.8%, and 90.3, respectively.

Conclusions

Preoperative diagnosis of thyroid nodules using TBSRTC in our hospital was comparable with other studies. The uniform diagnostic criteria of the Bethesda System help avoid misinterpretation while sharing local experience with international benchmarks.

The Use of Fine-Needle Aspiration (FNA) Cytology in Patients with Thyroid Nodules in Asia: A Brief Overview of Studies from the Working Group of Asian Thyroid FNA Cytology

Ultrasound-guided fine-needle aspiration (FNA) cytology is the most widely used screening and diagnostic method for thyroid nodules. Although Western guidelines for managing thyroid nodules and the Bethesda System for Reporting Thyroid Cytopathology are widely available throughout Asia, the clinical practices in Asia vary from those of Western countries. Accordingly, the Working Group of Asian Thyroid FNA Cytology encouraged group members to publish their works jointly with the same topic. The articles in this special issue focused on the history of thyroid FNA, FNA performers and interpreters, training programs of cytopathologists and cytotechnicians, staining methods, the reporting system of thyroid FNA, quality assurance programs, ancillary testing, and literature review of their own country’s products. Herein, we provide a brief overview of thyroid FNA practices in China, India, Japan, Korea, the Philippines, Taiwan, and Thailand.