Prognostic Impact of Internal Jugular Vein Invasion Through Extrathyroidal and Extranodal Extension in Papillary...

IJV invasion is a rare but significant occurrence in PTC. Although the current staging system categorizes T stages based on organ invasion, the classification for IJV invasion remains unclear. We evaluated the prognostic impact of internal jugular vein (IJV) involvement by extrathyroidal extension (ETE) and extranodal extension (ENE) in papillary thyroid carcinoma (PTC) and investigated the appropriate T-stage classification for ETE to the IJV.

This retrospective study included PTC patients who underwent surgery between 2005 and 2011 at our hospital. We analyzed patients with IJV resection due to ETE or ENE, dividing them into ETE and ENE groups. We also compared the ETE group's prognoses with those of patients with stage III or IV PTC to evaluate the T4a vs. T4b classification.

Among 5482 PTC cases, 17 were in the ETE group and 47 in the ENE group. We compared the ETE group's prognoses with those of the patients with stage III or IV PTC to evaluate the T4a vs. T4b classification. Compared to the ENE patients, the ETE patients had significantly lower 10-year overall survival (40.6% vs. 81.9%; HR 2.77, 95% CI: 0.99-7.67) and disease-specific survival (44.3% vs. 92.6%; HR 6.81, 95% CI: 1.68-27.51). Survival for ETE to the IJV was significantly worse than for stage III PTC but comparable to stage IV.

ETE to the IJV showed a poor prognosis, comparable to stage IV, whereas ENE to the IJV had a favorable prognosis even though we did not exclude the presence of high-risk factors. ETE to the IJV represents an aggressive disease course in PTC, warranting careful consideration in staging and treatment planning.