Rates of Incidental Thyroid Nodule and Thyroid Cancer Detection in Routine Check-up Examinations: A Single-center Study

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Bağcılar Tıp Bülteni, vol.6, no.3, pp.248-256, 2021 (Peer-Reviewed Journal) identifier


Objective: Check-up examinations have gained importance in the last decade and become a common reason for people to refer to healthcare institutions to seek medical help. Thyroid nodules are frequently detected during check-up examinations. This study aimed to determine the frequency of thyroid nodules and the rate of thyroid cancer development in patients presenting for a check-up and to define the role of variables in thyroid cancer detection. Method: The computer database of the patients, who applied for a check-up examination, was systematically screened, and the records of thyroid ultrasonography (US) were accessed. Patients with any known history of thyroid disease or thyroid cancer and those using medication for an existing thyroid disease were excluded. The demographic data, thyroid US reports, cytology and histopathology results, and free t3 (fT3), free t4 (fT4), and thyroid-stimulating hormone (TSH) levels were evaluated and recorded. Body mass index (BMI) was calculated. Data were analyzed using SPSS v. 25. Results: Of the 30,449 check-up patients, 24,362 were evaluated. Incidental thyroid nodules were detected in 5.645 (23.17%) patients. The mean BMI of these patients was 56±2.01 kg/m², and their mean TSH, fT3 and fT4 values were 2.87±0.45 mIU/mL, 3.76±0.87 pg/mL and 1.23±0.24 pg/mL, respectively. The mean nodule size was 1.31±0.56 mm. While 2.936 (52.01%) of the nodules were solid, 1.377 (24.39%) were cystic and 1.332 (23.59%) were mixed. Of all the nodules, 1.916 (33.94%) were in the TIRADS 2 category, 3.273 (57.98%) in the TIRADS 3 category, 234 (4.31%) in the TIRADS 4a category, 114 (1.27%) in the TIRADS 4b category, 72 (1.27%) in the TIRADS 4c category, and 36 (0.63%) in the TIRADS 5 category. For 392 patients that underwent a biopsy, the results were reported as benign for 224 (57.14%), suspected malignancy for 100 (25.51%), and malignant for 68 (17.34%). The rates of patients diagnosed with papillary, follicular and medullary thyroid cancers were 63.15%, 34.21% and 2.63%, respectively. When the multinominal logistic regression analysis was applied to all significant variables in the univariate analysis, the risk of thyroid cancer was increased 1.7-fold by increased BMI [odds ratio (OR): 1.71, 95% confidence interval (CI): 1.43-2.96], 1.8- fold by female gender [OR: 1.79, (CI): 1.21-2.67], 1.6-fold by solid structure nodule type [OR: 1.62, (CI): 1.27-3.54], 2.7-fold by increased nodule size [OR: 2.71, (CI): 1.11-3.31], and 4.7-fold by increased TIRADS [OR: 4.73, (CI): 1.76-7.31]. Conclusion: The main difficulty in evaluating and managing thyroid nodules is to avoid the inappropriate overuse of thyroid US, thyroid biopsy, and surgery while trying to identify clinically significant malignant nodules. Concerning the diagnosis of thyroid cancer through a checkup examination, the data obtained as a result of more detailed studies should be evaluated, and it should be kept in mind that the increase in the incidence of thyroid cancer in the last three decades may be due to not only overdiagnosis but also a real increase in incidence. However, considering that early diagnosis of thyroid cancer without lymph node involvement can reduce both surgical complications and prevent the risks of radioactive iodine treatment, it is concluded that thyroid cancer being detected at an early stage constitutes an important advantage for the healthy population undergoing a check-up.