A single institution experience on the correlation of Kwak Thyroid Imaging Reporting and Data System Score (Kwak TIRADS) and Malignancy of Thyroid Nodules seen in a Tertiary Hospital Setting

Objective: The purpose of this study is to determine the diagnostic accuracy of a surgeon-performed thyroid ultrasound reported using Kwak Thyroid Imaging Reporting and Data System (Kwak TIRADS) in identifying thyroid malignancy. Patients and Methods: This is a retrospective cohort study of patients who underwent preoperative thyroid ultrasound by a surgeon and subsequently underwent thyroidectomy from January 2018 – March 2020 in UP-PGH, Department of Surgery. Correlation between ultrasonographic features and Kwak TIRADS categories with malignancy were analyzed using chi square (univariate analysis) and logistic regression (multivariate analysis). Results: A total of 174 patients with thyroid nodules at least 1 cm in widest diameter were included in the study. There were 85 patients with malignant thyroid disease and 89 patients with benign nodules. Solid composition, hypoechogenicity/marked hypoechogenicity, lobulated/irregular margins, rim/microcalcifications, and shape taller than wide were significantly associated with thyroid malignancy on univariate analysis (all p-values < 0.001). However, only solid composition, hypoechogenicity/marked hypoechogenicity, and irregular/lobulated margins were significantly associated with thyroid malignancy on multivariate analysis (p-values < 0.001, 0.002 and 0.011, respectively). On the other hand, Kwak TIRADS categories 4a and above are significantly associated with thyroid malignancy (all p-values < 0.001), with the risk of malignancy increasing as the Kwak TIRADS category increases. Sensitivity, specificity, PPV and negative NPV are optimal when cutoff for further workup is set at Kwak TIRADS 4a. Conclusions: A surgeon performed thyroid ultrasonography reported using Kwak TIRADS classification can be utilized as a guide in the management of thyroid nodules. The consideration of Kwak TIRADS 4a as a cutoff level for further workup is recommended.