Endocrine Abstracts

Background: The risk of thyroid cancer in large thyroid nodules greater than 4 cm has been reported to be increased. Some authors insist that diagnostic lobectomy should be performed in patients with large thyroid nodules, irrespective of fine needle aspiration cytology (FNA) results. However, consensus on that matter has not been met. We wanted to investigate the risk of thyroid malignancy according to the size of the thyroid nodules, based on FNA results.

Methods: FNA results of 836 patients with thyroid nodules larger than 2 cm who visited Chonnam National University Hwasun Hospital from April 2004 to March 2009 were evaluated according to size category. The nodules were categorized to three groups by maximal diameter of the nodule on ultrasonography (Group A: 2–2.9 cm, Group B: 3–3.9 cm, Group C: ≥4 cm).

Results: Number of patients in group A, B and C were 476, 206 and 154 and the mean sizes of the nodules in each group were 2.4±0.3 cm, 3.4±0.3 cm, and 4.9±1.0 cm, respectively. Based on ATA ultrasonographic category, high suspicion nodules were 51(10.7%), 13 (6.3%), and 9 (5.8%, P=0.073). After FNA, the Bethesda system 6 category were reported in 32 (6.7%), 14 (6.8%) and 8 (5.2%), in each group and there was no increased risk of malignancy in larger thyroid nodules (P=0.887).

Conclusions: Large thyroid nodules (≥4 cm) are not at higher risk for malignancy. Surgical decision should be guided by FNA result of the nodule, not by the size the nodule.