Endocrine Abstracts

Background: Most thyroid nodules are benign therefore, they are commonly only monitored. Only a few studies are available on the natural progression/regression of benign thyroid nodules, and large-scale studies on the subject are non-existent. So we identify factors that affect the size of benign thyroid nodules and to predict the potential nodule size through a model.

Methods: Between January 2001 and December 2011, 2,469 benign thyroid nodules (1,564 patients) were diagnosed through fine needle aspiration. After excluding 505 nodules for which either the volume was unknown or percutaneous ethanol injection or radiofrequency ablation had been performed, 1,964 benign thyroid nodules (1,261 patients) were selected for the retrospective analysis in our study.

Results: The nodules with increased size overtime involved a longer follow-up period than the nodules with decreased size. The proportions of females and cystic portion were relatively high. For the thyroid nodules with increased size, we analysed the potential influencing factors. Our analysis results indicate that larger nodule volume, extended follow-up period, and high cystic proportion were all positively associated with increased nodule size.

Conclusion: Controlling for all other potential variables, the thyroid nodules tended to grow at a rate of approximately 0.034 cm³ per year in the group with continually growing nodules. The model used in our study may offer helpful insight in determining an optimal treatment schedule for benign thyroid nodules.