Diagnostic Efficacy and Safety of Core Needle Biopsy as a First-Line Diagnostic Method for Thyroid Nodules: A Prospective Cohort Study

Background: The diagnostic role of ultrasonography (US)-guided core needle biopsy (CNB) as a first-line diagnostic method for thyroid nodules remains controversial. This study was performed to determine the diagnostic efficacy and safety of CNB as a first-line diagnostic method for thyroid nodules. Methods: From February 2016 to January 2018, CNB was prospectively performed by an experienced radiologist in all consecutive patients with thyroid nodules indicated for fine-needle aspiration (FNA). Three patients refused this protocol. Finally, 212 consecutive patients with 248 thyroid nodules were enrolled in this prospective study. Combined CNB/FNA was selectively performed in 43 patients. The diagnostic efficacy of CNB was evaluated by the rate of inconclusive results (nondiagnostic or indeterminate results), and its feasibility was estimated by calculating the successful biopsy rate and by measuring the procedure time from the time of the initial skin puncture to the last withdrawal of the biopsy needle from the skin. The safety of the procedure was evaluated by the major and minor complication rates. A US evaluation was performed before and after manual self-compression to assess for hemorrhage at the biopsy site, and delayed complications were assessed 5-7 days after the biopsy. Any hemorrhage that did not require hospitalization was classified as a minor complication. Results: CNB was performed once (n = 125, 50.4%), twice (n = 122, 49.2%), or three times (n = 1, 0.4%) per nodule. The diagnostic results of CNB were as follows: nondiagnostic (0.8%), benign (63.3%), indeterminate (10.1%), follicular neoplasm (3.2%), suspected malignancy (2.4%), and malignancy (20.1%); the rate of inconclusive results was 10.9%. The successful biopsy rate of CNB was 100%, and the median procedure time was 102 seconds (interquartile range 51-181 seconds). There were no major or delayed complications. There were 6 cases (2.8%) of minor complications, which included 2 cases (0.9%) with symptomatic hematomas and 4 cases (1.9%) with asymptomatic small hematomas. Conclusion: The findings confirm that CNB is effective in reducing the rate of inconclusive results and it is safe. CNB may be used as an alternative first-line diagnostic method for thyroid nodules by an experienced operator.