A One-Year Cross-Sectional Study on the Impact of the Thyroid Imaging Reporting and Data System (TIRADS) on Fine-Needle Aspiration Cytology (FNAC) Decision-Making in a Secondary Care Hospital

Introduction: The widespread utilization of neck ultrasound (US) by family physicians for the investigation of non-specific neck symptoms, as well as by endocrinologists and general surgeons for symptomatic thyroid problems, has led to an increase in the detection of nonpalpable thyroid nodules. This presents challenges and dilemmas regarding the decision to perform fine-needle aspiration cytology (FNAC). The routine use of cytology is often considered unnecessary, costly, and inconvenient for patients. Therefore, this observational study was conducted to explore how FNAC could be avoided by using the Thyroid Imaging Reporting and Data System (TIRADS), drawing insights from comparative data analysis with the Bethesda cytology system and postoperative histopathology. Objective: This study aims to observe trends in decision-making for performing FNAC using only the US TIRADS scoring, without considering nodule size, by comparing the results with histopathology of the operated patients and recommending conclusions. Material and methods: Data were collected over a one-year period from January 1, 2023, to December 31, 2023, from the hospital's electronic medical records, resulting in 89 cases for analysis and comparison. All thyroid nodule cases with a US TIRADS score were included in the study, while post-total thyroidectomy cases as follow-up and patients who died during the study period were excluded. Results: Among the 89 cases, US-guided FNAC was performed in 37 cases (41.5%). In 38 cases (42.5%), FNAC was not recommended by the clinician, while in the remaining cases, it was advised but not performed due to patient refusal (27.5%). For TIRADS score 1, no FNAC was performed. In TIRADS score 2, FNAC was conducted in two out of 19 cases, both confirmed as benign. For TIRADS score 3, among 22 FNAC cases, one was categorized as Bethesda 3, while the rest had Bethesda scores of 2 or lower; none underwent surgery. In TIRADS score 4, FNAC was performed in 12 cases, with four classified as Bethesda 4, all of whom underwent surgery. One of these cases was confirmed as malignant. In TIRADS score 5, a single case was identified, which yielded a Bethesda 5 result on FNAC and was later confirmed as malignant on postoperative histopathology. Overall, 37 out of 89 cases (41.5%) underwent FNAC, with five cases proceeding to surgery (13%). Histopathological analysis confirmed malignancy in two cases, resulting in an overall malignancy rate of 5.5% among FNAC cases. Conclusions: Patient reluctance toward FNAC due to concerns over discomfort and complications remains a barrier. FNAC is generally not indicated for TIRADS categories 1 and 2. In our study, FNAC appeared unwarranted for TIRADS category 3, as none of these patients underwent surgery despite constituting 60% of the cohort, aligning with literature that reports a malignancy risk of under 5% in this category. Such nodules may be better managed through periodic surveillance and individualized risk stratification based on factors such as patient age and nodule size. In contrast, FNAC was justified and appropriately applied in TIRADS 4 and 5 categories, which carry a higher risk of malignancy. Although nodule size was not analyzed in this study, the results are consistent with previously established data.