Abstract
Of 7348 evaluated nodules, 927 (13%) were cancerous. Of those 1.0 to 1.9 cm in diameter, 10.5% were cancerous.
In contrast, of those >2.0 cm, 15% were cancerous (P 4 cm were cancerous in 14%, 16%, and 15% of cases (P = .14), respectively, demonstrating no graded increase in risk beyond the 2-cm threshold. When malignant, the proportion of papillary carcinoma decreased (nodules 1.0-1.9 cm, 92% of cases; 2.0-2.9 cm, 88%; 3.0-3.9 cm, 83%; >4 cm, 74% [P 4 cm, 16% [P < .01]) as nodules enlarged.
Nodules size did not influence cytology distribution or risk of false-negative aspirates. Increasing thyroid nodule size impacts cancer risk in a nonlinear fashion.
A threshold is detected at 2.0 cm, beyond which cancer risk is unchanged. However, the risk of follicular carcinomas and other rare thyroid malignancies increases as nodules enlarge.