Impact of Nodule Size on Malignancy Risk Differs according to the Ultrasonography Pattern of Thyroid Nodules

• Published in: Korean Journal of Radiology Vol. 19; no. 3; pp. 534 - 541
• Main Authors: Hong, Min Ji, Baek, Jung Hwan, Sung, Jin Yong, Kim, Ji-Hoon
• Format: Journal Article
• Language: English
• Published: Korea (South) The Korean Society of Radiology 01.05.2018; 대한영상의학회
• Subjects: Adult; Aged; Chi-square test; Female; Humans; Image Processing, Computer-Assisted; Lymphoma; Male; Middle Aged; Retrospective Studies; Risk; Thyroid; Thyroid cancer; Thyroid Neoplasms; Thyroid Nodule; Tumors; Ultrasonic imaging; Ultrasonography; 방사선과학; United States > US; Japan; Thyroid malignancy; Imaging analysis; Imaging feature; Tumor size; Ultrasonography; Nodule size; Thyroid nodule; Imaging pattern; Risk of malignancy; Malignancy risk; Pattern analysis; Thyroid
• ISSN: 1229-6929; 2005-8330; 2005-8330
• DOI: 10.3348/kjr.2018.19.3.534

To test whether the impact of thyroid-nodule size on the malignancy risk differs according to the ultrasonography (US) patterns of nodules. This study is a post hoc analysis using data from the Thyroid Imaging Reporting and Data System (TIRADS) multicenter retrospective study which included 2000 consecutive thyroid nodules (≥ 1 cm) with final diagnoses. A total of 2000 consecutive thyroid nodules from 1802 patients (1387 women and 613 men; mean age, 51.2 ± 12.2 years) were enrolled in this study. The malignancy risk of the nodules was assessed according to the nodule size and US patterns (Korean-TIRADS). Overall, the malignancy risk did not increase as nodules enlarged. In high-suspicion nodules, the malignancy rate had no association with nodule size ( = 0.467), whereas in intermediate- or low-suspicion nodules there was a trend toward an increasing malignancy risk as the nodule size increased ( = 0.004 and 0.002, respectively). The malignancy rate of large nodules (≥ 3 cm) was higher than that of small nodules (< 3 cm) in intermediate-suspicion nodules (40.3% vs. 22.6%, respectively; = 0.001) and low-suspicion nodules (11.3% vs. 7.0%, respectively; = 0.035). There was a trend toward a decreasing risk and proportion of papillary carcinoma and an increasing risk and proportion of follicular carcinoma or other malignant tumors as nodule size increased ( < 0.001, respectively). The impact of nodule size on the malignancy risk differed according to the US pattern. A large nodule size (≥ 3 cm) showed a higher malignancy risk than smaller nodules in intermediate- and low-suspicion nodules.