Abstract Background The prognostic relevance of minimal extrathyroidal extension (mETE) in early-stage, node-negative papillary thyroid carcinoma (PTC) remains debated. While gross extrathyroidal invasion is a well-established predictor of recurrence, the impact of mETE is less clear. This study evaluated the association between mETE and disease-free survival (DFS) in T1b–T2N0 PTC. Methods We retrospectively reviewed 1,195 patients who underwent total thyroidectomy for PTC between 2000 and 2022. Tumours were classified as T1b (1–2 cm) or T2 (2–4 cm) and stratified by the presence of mETE. Clinicopathologic variables were compared, and recurrence predictors were assessed using univariate and multivariate Cox regression. DFS was analysed with Kaplan–Meier methods. Results Among 819 T1b tumours, mETE was found in 227 patients (27.7%) and correlated with vascular invasion (14.1% vs. 2.9%, p0.001). DFS was similar between groups (10-year DFS: 98.3% vs. 96.5%, p=0.053). Although recurrence risk increased with mETE (HR 2.35; 95% CI 0.96–5.79), this was not statistically significant, and mETE was not an independent predictor. Among 376 T2 tumours, mETE was present in 71 patients (18.9%) and was associated with larger tumour size, multifocality, bilaterality, and vascular invasion. mETE significantly reduced DFS (p0.0001), with 10-year DFS of 97.6% (no mETE) versus 88.4% (mETE). It remained an independent predictor of recurrence (HR 3.58; 95% CI 1.24–10.33). Conclusions In early-stage, node-negative PTC, mETE does not significantly affect DFS in T1b tumours but is a strong, independent predictor of recurrence in T2 tumours. T2N0 PTC with mETE may warrant intermediate-risk classification and intensified surveillance.
Hamzaoui et al. (Fri,) studied this question.