Prognostic factors for aggressiveness in subcentimeter papillary thyroid carcinoma: impact of tumor size and lymph node metastases.

Objective: Subcentimeter papillary thyroid carcinoma (sPTC), also known as papillary thyroid microcarcinoma, is associated with a good prognosis and low mortality risk. However, some sPTCs exhibit biologically aggressive characteristics. The aim of this study was to identify factors affecting the prognosis and aggressiveness of sPTC by considering the demographic characteristics of patients with sPTC and the pathologic characteristics of the tumors.

Subjects and methods: The study included 255 patients aged ≥ 18 years who were operated on at Ondokuz Mayis University, Faculty of Medicine (Samsun, Turkey) between June 2008 and December 2021. All patients had histopathologic confirmation of sPTC (≤10 mm) and underwent regular follow-up for at least 36 months.

Results: The tumors had a mean size of 5 mm (0.1-10 mm) and were multifocal in 53.7% of patients. Capsular invasion was observed in 9% of patients. Vascular invasion, lymphatic invasion, and extrathyroidal invasion were present in 2%, 5.5%, and 0.8% of patients, respectively. Metastatic cervical lymph nodes were observed in 9.4% of patients. On multivariate logistic regression analysis, tumor size (odds ratio [OR] 1.380, 95% confidence interval [CI] 1.106-1.722, p = 0.004) and sex (OR 4.233, 95% CI 1.355-13.226, p = 0.013) were the main predictive factors influencing lymph node metastasis. Tumors > 5 mm, compared with tumors ≤ 5 mm, had higher rates of multifocality (p = 0.009), parenchymal invasion (p = 0.008), calcifications (p = 0.001), microscopic lymphatic invasion (p = 0.002), and presence of metastatic lymph nodes (p < 0.001).

Conclusion: The findings of this study highlight important factors to consider in making decisions about prophylactic central compartment neck dissection in patients with sPTCs, particularly those with clinically node-negative tumors.