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Relationship between Capsule Invasion and Ultrasound Imaging in Thyroid Cancer
J Surg Ultrasound 2020;7:15-20
Published online November 30, 2020;
© 2020 The Korean Surgical Ultrasound Society

Sung Keun Kang, Bong Kyun Kim, Woo Young Sun, Jina Lee

Department of Surgery, Daejeon St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Daejeon, Korea
Correspondence to: Jina Lee
Department of Surgery, Daejeon St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, 64 Daeheung-ro, Jung-gu, Daejeon 34943, Korea
Tel: +82-42-220-9427
Fax: +82-42-220-9520
Received June 17, 2020; Revised September 9, 2020; Accepted September 9, 2020.
Journal of Surgical Ultrasound is an Open Access Journal. All articles are distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Purpose: The main aim of this study was to determine if preoperative ultrasonography (US) of thyroid cancer can predict a pathologic invasion over the thyroid capsule and be used as an indicator in deciding the range of thyroidectomy.
Methods: A retrospective analysis was conducted on 408 patients who underwent a total thyroidectomy due to thyroid cancer. Among 408 patients, 254 patients showed pathologic capsular invasion, and 154 did not. The patients were categorized into three groups according to the relationship between the tumor and thyroid capsule shown in preoperative US. The clinical, sonographic, and pathologic data from each group were analyzed.
Results: The accuracy of preoperative US to predict pathologic capsular invasion by measuring the relationship between the thyroid capsule and cancer mass showed a sensitivity of 0.71, specificity of 0.55, and positive predictive value (PPV) of 0.72. On the other hand, the negative predictive value (NPV) was 0.53. Patients with pathologic capsule invasion showed a significant difference in cancer mass size and total harvested lymph nodes postoperatively compared to those without a capsule invasion. Multivariate analysis to determine the factors affecting the relapse of thyroid cancer after surgery, including clinical, sonography, and pathologic features, showed no significant difference except for female gender.
Conclusion: A preoperative US examination on its own is not enough to determine pathologic capsular invasion.
Keywords : Thyroid cancer, Ultrasonography, Thyroidectomy

November 2020, 7 (2)