Background We aimed to investigate the prognostic significance of primary tumor size in patients with pT1–T3a N0 M0 papillary thyroid carcinoma (PTC), minimizing the impact of confounding factors.
Methods A multicenter retrospective study included 5,759 patients with PTC. Those with lymph node metastasis, gross extrathyroidal extension (ETE), and aggressive variants were excluded. Patients were categorized by primary tumor size (≤1, 1.1–2, 2.1–4, and >4 cm) and subdivided based on the presence of microscopic ETE (mETE).
Results The median age was 48.0 years, and 87.5% were female. The median primary tumor size was 0.7 cm, with mETE identified in 43.7%. The median follow-up was 8.0 years, with an overall recurrent/persistent disease rate of 2.8%. Multivariate analysis identified male sex, larger tumor size, and the presence of mETE as significant prognostic risk factors. The 10-year recurrent/persistent disease rates for tumors ≤1, 1.1–2, 2.1–4, and >4 cm were 2.5%, 4.7%, 11.1%, and 6.0%, respectively. The 2.1–4 cm group had a significantly higher hazard ratio (HR), with the >4 cm group had the highest HR than the ≤1 cm group. Patients with mETE had a higher recurrent/persistent disease rate (4.5%) than those without, with rates by tumor size being 2.6%, 5.6%, 16.7%, and 8.2%.
Conclusion Larger tumor size and the presence of mETE significantly increased the risk of recurrent/persistent disease in PTC. Patients with pT2–T3a N0 M0 PTC (>2 cm) had a recurrent/persistent disease risk exceeding 5%, warranting vigilant management.
Background Laryngotracheal invasion occurs in a subset of patients with well-differentiated thyroid cancer (WDTC) and is associated with a poor prognosis. We aimed to analyze patterns and predictors/outcomes related to this high-risk manifestation.
Methods This population-based analysis utilized the Surveillance, Epidemiology, and End Results (SEER) registry (2000 to 2015) to identify WDTC patients. Temporal trends and geographic variation in invasion rates were assessed. Logistic regression and propensity score matching were employed to identify predictors of secondary malignancy, mortality, and treatment impact on overall and thyroid cancer (TC)-specific survival.
Results Of 131,721 WDTC patients, 1,662 (1.3%) had tracheal invasion and 976 (0.7%) had laryngeal invasion at diagnosis. Tracheal and laryngeal invasion rates declined from 3.7%–0.7% and 1.5%–0.6%, respectively, from 2000 to 2015. Compared to 98,835 noninvasive cases, patients with laryngotracheal invasion were older and more often male, Asian, and Hispanic (all P<0.001). This group had larger tumors with higher rates of nodal (N1: 61.8% vs. 15.1%) and distant metastases (M1: 9.3% vs. 0.4%). Age ≥55 years (hazard ratio [HR], 1.19; P=0.004) and metastases (HR, 1.75; P<0.001) increased TC-specific mortality, whereas the converse pattern was found for Asian race (HR, 0.63; P=0.002) and surgery (HR, 0.35; P<0.001). In rigorously matched groups to control confounding, adding radioactive iodine to surgery reduced mortality by 30% (P<0.001). However, external beam radiation and systemic therapy did not improve survival over surgery alone.
Conclusion Laryngotracheal invasion is present in 0.7% to 1.3% of cases, conferring over double the mortality risk. Radioactive iodine with surgery improves outcomes in this aggressive WDTC subset.