Cytological findings of thyroid fine-needle aspirations undertaken at Chris Hani Baragwanath Academic Hospital from January 2016 to December 2019

Abstract

Introduction Thyroid nodules are commonly encountered in clinical practice, with thyroid cancer being the most frequent endocrine malignancy seen. There is limited data regarding the outcomes of thyroid nodules in a low-resource environment. A reliable preoperative diagnosis will facilitate prompt treatment of malignancy as well as limit the need for unnecessary interventions. Objectives To describe the cytological characteristics of thyroid nodules at Chris Hani Baragwanath Academic Hospital (CHBAH) and to compare the outcomes of thyroid fine-needle aspiration (FNA) based on the FNA setting as well as the method of FNA. In addition, to compare the accuracy of preoperative thyroid FNAs and the postoperative histopathological thyroid diagnosis. Method A retrospective descriptive study of thyroid nodule FNA results at CHBAH over the period 2016 – 2019. Frequencies and percentages were used to summarise the data. Results In our study, 600 cytology specimens were reviewed. The median age of the study population was 52 years (IQR 42 – 62 years), with 516 females and 78 males. There was a higher incidence of female patients, 516 (86%) with thyroid nodules. A higher incidence of malignant nodules was seen in male patients. No correlation was found between thyroid-stimulating hormone (TSH) levels and malignancy. Thyroid nodule FNAs were performed at 3 different sites, with 112 samples (18.7%) being nondiagnostic. Specimens performed at the cytopathology clinic by palpation guidance yielded the most nondiagnostic samples (25.1%), compared to 8.1% at the endocrine clinic and 16.1% at the radiology clinic. From the cytology samples, 105 samples had corresponding histology specimens of which 43 samples (40.9%) were proven to be malignant. There was a statistically significant correlation between the cytological and histopathology samples (p <0.05). v Conclusion The prevalence of malignancy and gender distribution in our study are largely consistent with those of international studies. It demonstrates that thyroid nodule FNA is an effective tool in the diagnostic algorithm for thyroid nodules. However, nondiagnostic samples pose a diagnostic challenge. Our study demonstrated that ultrasound guided FNA samples are superior to palpation guided FNA samples as they yielded fewer nondiagnostic samples. A subset analysis demonstrated the advantage of a dedicated trained FNA operator over multiple operators. This is a feasible option in a low-resource environment where the availability of a US- machine or specialist may not be available.