PURPOSE: Thyroid nodules that increase in size during follow up are often regarded as suspicious for malignancy, and repeated biopsy is recommended. However, few studies have been conducted about this issue, and they have inconsistent conclusions. Therefore, the purpose of this study was to determine the natural course and growth predictors of cytologically benign thyroid nodules using ultrasonography.
MATERIAL AND METHODS: We collected the retrospective data for 1210 benign thyroid nodules from 1170 patients confirmed by Ultrasound-guided fine-needle aspiration biopsy from 2002.10.01 to 2004.03.17. A total of 844 benign thyroid nodules from 810 patients who had at least 2nd follow-up ultrasonography were included for the analysis. Nodule dimensions were measured at each visit, and growth criteria was defined as an increase in calculated volume of 15% or greater. These results were correlated with age, sex, time between examinations, multiplicity, cystic content and echogenicity of each nodule.
RESULTS: Mean follow up time was 47.24±27.72 (range:6-101). Operation was performed for 77 nodules, and 10 nodules (1.18%) were confirmed as malignancy. (9 nodules:papillary carcinoma, 1 nodule:minimally invasive follicular carcinoma) 300 nodules(35.55%) were increased, 351 nodules (41.59%) were decreased, and 193 nodules (22.86%) show no change in volume with a growth criteria defined as volume increase≥15%. Volume increased over time (p<0.0001). Nodules with ≥25% cystic component were less likely to grow than those with <25% cystic component. (p=0.002). Echogenicity of the nodule was not a significant growth predictor.
CONCLUSIONS: Most solid, benign thyroid nodules grow. Therefore, a increase in nodule volume is not a reliable predictor for malignancy.
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SS 07 TH-09.pdf
