|Year : 2020 | Volume
| Issue : 2 | Page : 69-72
Accuracy of fine-needle aspiration in diagnosing of well-differentiated thyroid cancer at a tertiary care center
Mazin A Merdad1, Zahra'a I Alghafli2, Sarah M AlSharif2, Marwah S AlQathmi2, Ghazi M Sindi2, Hani Z Marzouki1
1 Department of Otolaryngology-Head and Neck Surgery, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia
2 College of Medicine, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia
|Date of Submission||14-Apr-2020|
|Date of Decision||10-May-2020|
|Date of Acceptance||26-May-2020|
|Date of Web Publication||30-Dec-2020|
Dr. Mazin A Merdad
Department of Otolaryngology-Head and Neck Surgery, King Abdulaziz University, Jeddah
Kingdom of Saudi Arabia
Source of Support: None, Conflict of Interest: None
Background: Thyroid cancer is the third-most common cancer in Saudi females and males. The Bethesda System for Reporting Thyroid Cytopathology provides a diagnostic framework that can be used in surgical decision-making that allows the use of standardized treatment algorithms for each category. The present study aims to assess the accuracy of fine-needle aspiration (FNA) in diagnosing well-differentiated thyroid cancer in comparison to the corresponding final histopathological results. Methodology: This was a retrospective review of 404 patients who underwent FNA cytology, followed by thyroid surgery during 2010–2018. Data were collected from the medical records of these patients. Results: Based on the final histopathological examination results, 63% of the tested nodules were benign and 36% were malignant. The tested thyroid nodules with Bethesda categories II, III, IV, V, and VI were diagnosed as malignant in 8.7% 33.3%, 50%, 60%, and 94.4%, respectively. FNA (Bethesda categories II and VI) for benign and malignant lesions revealed a sensitivity, specificity, positive predictive value (PPV), and negative predictive value of 79.69%, 97.84%, 94.44%, and 91.28%, respectively. Conclusion: FNA is a reliable diagnostic tool for diagnosing thyroid nodules with a high specificity and PPV. The capability of the relatively high overall malignancy rate can be explained by the nature of our institution, being a major regional tertiary and cancer center. The size of the nodule and its location, body mass index, and age had no significant effect on the accuracy of the FNA.
Keywords: Bethesda System for Reporting Thyroid Cytopathology, fine-needle aspiration, malignancy risk, thyroid cancer
|How to cite this article:|
Merdad MA, Alghafli ZI, AlSharif SM, AlQathmi MS, Sindi GM, Marzouki HZ. Accuracy of fine-needle aspiration in diagnosing of well-differentiated thyroid cancer at a tertiary care center. Saudi J Otorhinolaryngol Head Neck Surg 2020;22:69-72
|How to cite this URL:|
Merdad MA, Alghafli ZI, AlSharif SM, AlQathmi MS, Sindi GM, Marzouki HZ. Accuracy of fine-needle aspiration in diagnosing of well-differentiated thyroid cancer at a tertiary care center. Saudi J Otorhinolaryngol Head Neck Surg [serial online] 2020 [cited 2021 Jan 19];22:69-72. Available from: https://www.sjohns.org/text.asp?2020/22/2/69/305458
| Introduction|| |
Approximately 53,990 patients are diagnosed with thyroid cancer annually in the United States. Similarly, thyroid cancer in Saudi Arabia accounts for 8.2% of all cancers. Moreover, it is the third-most common cancer in both female and male individuals and is the second-most common cancer in women.,,, During the last two decades, fine-needle aspiration (FNA) has emerged as the most simple and reliable tool for diagnosing thyroid nodules, with an estimated overall sensitivity and specificity of >90%., This study aims to assess the accuracy of FNA in diagnosing well-differentiated thyroid cancer by comparing it to the corresponding final histopathologic results. Moreover, the factors affecting the accuracy of FNA are assessed.
| Methodology|| |
Data were retrospectively collected from 404 patients who underwent thyroid surgery for well-differentiated thyroid cancer at King Abdulaziz University Hospital between 2010 and 2018. Our institutional review board approved the study. Data collected from the electronic medical records included demographic information of the patients (age, gender, and body mass index [BMI]), medical history, histopathological examination results (pathological diagnosis, size, and location of the lesion, volume of the nodule, and maximum diameter of the nodule), and sonographic test findings. Ultrasound-guided FNA (US-guided FNA) was performed for thyroid nodules of ≥ 1.0 cm in maximal dimension on ultrasonography. Both the site and size of the nodule assessed through biopsy were correlated to the final histopathological results to ensure that the same nodule was analyzed on both cytological and histological examinations. FNA results were classified according to the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). The final histopathological diagnosis was classified as benign or malignant. Statistical analysis was conducted using the Statistical Package for the Social Sciences software (SPSS),version 22, Chicago, IL, USA.
Inclusion and exclusion criteria
The study included well-differentiated thyroid cancer (papillary and follicular) between the years 2010 and 2018 and patients older than 15 years were included in the study. Patients with incomplete data or final pathology other than well-differentiated thyroid cancer (papillary and follicular) were excluded from the study.
| Results|| |
A total of 404 patients with complete data were included in the analysis. The mean age of our patients was 43.1 years, and 85% were women. The mean maximum diameter of the dominant nodule was 22.6 mm. The final histopathological examination revealed that 63% of the tested nodules were benign and 36% were malignant. The demographic characteristics of the participants and thyroid nodule variables are shown in [Table 1]. The Bethesda categorization of the FNA samples is depicted in [Figure 1]. Of the 51.2% benign lesions on FNA (Bethesda II), approximately 4.5% of the lesions were malignant based on the final histopathological examination, whereas the tested thyroid nodules with Bethesda categories III, IV, V, and VI were diagnosed as malignant in 33.3%, 50%, 60%, and 94.4%, respectively [Table 2]. Sensitivity, specificity, positive predictive value (PPV), and negative predictive values (NPV) of FNA (Bethesda categories II and VI) of the malignant and benign lesions are displayed in [Table 3]. International comparison of the Bethesda system is summarized in [Table 4].
|Table 2: Frequency and malignancy rates using The Bethesda System for Reporting Thyroid Cytopathology category|
Click here to view
|Table 3: Sensitivity analysis of benign and malignant fine-needle aspiration: (Bethesda categories II and VI)|
Click here to view
|Table 4: Comparison of percentage of cases in each Bethesda category and risk of malignancy on histopathology specimens between the present study and other studies from other countries|
Click here to view
| Discussion|| |
Thyroid cancer is the second-most common cancer among women in Saudi Arabia., This study aimed to assess the accuracy of FNA in diagnosing well-differentiated thyroid cancer and in detecting factors affecting the accuracy of FNA.
In our study, the overall risk of malignancy (ROM) according to the Bethesda categories of benign lesions, atypia of undetermined significance (AUS)/follicular lesion of undetermined significance (FLUS), and follicular neoplasms were 8.7%, 33.3%, and 50%, respectively. This is in contrast with the general ROM according to the guidelines showing the following rates of malignancy: 0%–3% for benign lesions, 5%–15% for AUS/FLUS, and 15%–30% for follicular neoplasms. Despite the fact that there is a new second edition of The Bethesda system for reporting thyroid cytopathology (TBSRTC) published, where the ROM and clinical management of noninvasive follicular thyroid neoplasm with papillary like nuclear features (NIFTP) was demonstrated. Yet, NIFTP cytological features were not used in this study, so we compared our results with first edition of TBSRTC. Other institutions have previously reported higher ROM using the TBSRTC.,,,, In addition, a recent meta-analysis of three registries (CESQIP, Eurocrine, and UKRETS) reported higher ROM for the lower Bethesda diagnostic categories (I, II, and III) in 19.2%, 12.7%, and 31.9%, respectively. We compared our results with multiple international studies and are summarized in [Table 4].,,, The higher rates of malignancy were noted in Bethesda category II (benign), which could be explained by the local referral system and the fact that some of the FNA reports were conducted in other institutions. Furthermore, our institution up to last year did not have a dedicated head and neck pathologists and cytopathologists, and this could have affected the accuracy of reporting. The ROM in our study for suspicious and malignant lesions based on FNA was comparable to those of most publications, including the National Cancer Institute guidelines.
Several factors affect the accuracy of FNA in diagnosing thyroid nodules, including size and location of the lesions, BMI, and age.,,, Pinchot et al. found that the size of the nodule (>4 cm) is correlated to a false-negative rate of 8%. However, in our study, the size and location of the lesion, BMI, and age had no statistically significant effect on the accuracy of the FNA.
The analysis of FNA in our cohort revealed a sensitivity of 79.7%, specificity of 97.8%, PPV of 94.4%, and NPV of 91.3%. Our overall results are in accordance with those of other published results, where the FNA cytology sensitivity was between 70% and 92% and the specificity was between 74% and 99%.,,,, This revalidates that FNA cytology is more specific than sensitive in detecting thyroid malignancy. FNA is the only one component of thyroid nodule assessment. Ancillary information for risk stratification (patient age, nodule size, sonographic features, and the presence of lymphadenopathy) decides the optimal treatment approach.
The limitation of this study includes its retrospective nature, wherein the enrolled patients were managed by variant teams and assessed by different cytopathologists. In addition, there were some inconsistencies in our medical records. The current study evaluated patients from a single tertiary institution, and the findings might not be reflective of the overall general practices and population.
Newer molecular tests, such as Afirma and ThyroSeq, have the ability to better categorize the cytologically indeterminate nodules' Bethesda categories (III and IV) according to their ROM. Such ancillary instruments can be used for further association with clinicopathological characteristics and the improvement of risk stratification in indeterminate nodules. Incorporating genetic tests in the thyroid nodule investigation algorithm may help some patients avoid unnecessary surgery.
| Conclusion|| |
FNA remains a reliable method for categorizing thyroid nodules with excellent specificity. Our study reported a generally higher rate of malignant nodules. Size of the nodule and its location, BMI, and age had no significant effect on the accuracy of the FNA.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Hussain F, Iqbal S, Mehmood A, Bazarbashi S, ElHassan T, Chaudhri N. Incidence of thyroid cancer in the Kingdom of Saudi Arabia, 2000-2010. Hematol Oncol Stem Cell Ther 2013;6:58-64.
Salim EI, Moore MA, Al-Lawati JA, Al-Sayyad J, Bazawir A, Bener A, et al
. Cancer epidemiology and control in the Arab World – Past, present and future. Asian Pac J Cancer Prev 2009;10:3-16.
Marzouki H. Accuracy of fine needle aspiration in diagnosing thyroid cancer in a tertiary care Centre. Ann Thyroid Res 2016;2: :P.039.
Bhatki AM, Brewer B, Robinson-Smith T, Nikiforov Y, Steward DL. Adequacy of surgeon-performed ultrasound-guided thyroid fine-needle aspiration biopsy. Otolaryngol Head Neck Surg 2008;139:27-31.
Tee YY, Lowe AJ, Brand CA, Judson RT. Fine-needle aspiration may miss a third of all malignancy in palpable thyroid nodules: A comprehensive literature review. Ann Surg 2007;246:714-20.
Cibas ES, Ali SZ; NCI Thyroid FNA State of the Science Conference. The Bethesda system for reporting thyroid cytopathology. Am J Clin Pathol 2009;132:658-65.
Ferlay JS, Ervik M, Dikshit R, Eser S, Mathers C, Rebelo M, et al
. Cancer Incidence and Mortality Worldwide. IARC CancerBase; 2012.
Cibas ES, Ali SZ. The 2017 Bethesda system for reporting thyroid cytopathology. Thyroid 2017;27:1341-6.
Arul P, Akshatha C, Masilamani S. A study of malignancy rates in different diagnostic categories of the Bethesda system for reporting thyroid cytopathology: An institutional experience. Biomed J 2015;38:517-22.
Bernstein JM, Shah M, MacMillan C, Freeman JL. Institution-specific risk of papillary thyroid carcinoma in atypia/follicular lesion of undetermined significance. Head Neck 2016;38 Suppl 1:E1210-5.
Yang J, Schnadig V, Logrono R, Wasserman PG. Fine-needle aspiration of thyroid nodules: A study of 4703 patients with histologic and clinical correlations. Cancer 2007;111:306-15.
Jo VY, Stelow EB, Dustin SM, Hanley KZ. Malignancy risk for fine-needle aspiration of thyroid lesions according to the Bethesda system for reporting thyroid cytopathology. Am J Clin Pathol 2010;134:450-6.
Park JH, Yoon SO, Son EJ, Kim HM, Nahm JH, Hong S. Incidence and malignancy rates of diagnoses in the Bethesda system for reporting thyroid aspiration cytology: An institutional experience. Korean J Pathol 2014;48:133-9.
Inabnet WB 3rd
, Palazzo F, Sosa JA, Kriger J, Aspinall S, Barczynski M, et al
. Correlating the Bethesda system for reporting thyroid cytopathology with histology and extent of surgery: A review of 21,746 patients from four endocrine surgery registries across two continents. World J Surg 2020;44:426-35.
Alshaikh S, Harb Z, Aljufairi E, Almahari SA. Classification of thyroid fine-needle aspiration cytology into Bethesda categories: An institutional experience and review of the literature. Cytojournal 2018;15:4.
] [Full text]
Kiernan CM, Broome JT, Solórzano CC. The Bethesda system for reporting thyroid cytopathology: A single-center experience over 5 years. Ann Surg Oncol 2014;21:3522-7.
Sarkis LM, Norlen O, Aniss A, Watson N, Delbridge LW, Sidhu SB, et al
. The Australian experience with the Bethesda classification system for thyroid fine needle aspiration biopsies. Pathology 2014;46:592-5.
Williams BA, Bullock MJ, Trites JR, Taylor SM, Hart RD. Rates of thyroid malignancy by FNA diagnostic category. J Otolaryngol Head Neck Surg 2013;42:61.
Pinchot SN, Al-Wagih H, Schaefer S, Sippel R, Chen H. Accuracy of fine-needle aspiration biopsy for predicting neoplasm or carcinoma in thyroid nodules 4 cm or larger. Arch Surg 2009;144:649-55.
Shrestha M, Crothers BA, Burch HB. The impact of thyroid nodule size on the risk of malignancy and accuracy of fine-needle aspiration: A 10-year study from a single institution. Thyroid 2012;22:1251-6.
Bessey LJ, Lai NB, Coorough NE, Chen H, Sippel RS. The incidence of thyroid cancer by fine needle aspiration varies by age and gender. J Surg Res 2013;184:761-5.
Ko HM, Jhu IK, Yang SH, Lee JH, Nam JH, Juhng SW, et al
. Clinicopathologic analysis of fine needle aspiration cytology of the thyroid. A review of 1,613 cases and correlation with histopathologic diagnoses. Acta Cytol 2003;47:727-32.
Ravetto C, Colombo L, Dottorini ME. Usefulness of fine-needle aspiration in the diagnosis of thyroid carcinoma: A retrospective study in 37,895 patients. Cancer 2000;90:357-63.
Guhamallick M, Sengupta S, Bhattacharya N, Basu N, Roy S, Ghosh A, et al
. Cytodiagnosis of thyroid lesions-usefulness and pitfalls: A study of 288 cases. J Cytol 2008;25:6-9. [Full text]
Bista M, K C T, Regmi D, Maharjan M, Kafle P, Shrestha S. Diagnostic accuracy of fine needle aspiration cytology in thyroid swellings. J Nepal Health Res Counc 2011;9:14-6.
Agrawal S. Diagnostic accuracy and role of fine needle aspiration cytology in management of thyroid nodules. J Surg Oncol 1995;58:168-72.
[Table 1], [Table 2], [Table 3], [Table 4]