Correlation of minimal extrathyroidal extension with pathologic features of lymph node metastasis in patients with papillary thyroid carcinoma.

Abstract

The impact of minimal extrathyroidal extension (mETE) to the prognosis of patients with papillary thyroid carcinoma (PTC) is controversial. In this study, we investigated whether mETE is related to the aggressive biology of metastatic lymph node (LN) in patients with PTC. A retrospective review of 369 patients who had biopsy-confirmed cervical LN metastasis after initial surgery for PTC was conducted. The correlations of mETE with the specific features of metastatic LNs such as the LN size, number, LN ratio, and presence of extranodal extension (ENE) were statistically analyzed. Size of the primary tumor (≥1 cm) had independent correlations to mETE (HR = 5.750). While mETE was related to number of metastatic LNs (≥5), LN ratio (≥0.31) and ENE in univariate analysis, only ENE (HR = 2.322) was independently correlated to mETE in our series. Along with mETE, size of primary tumor (≥1 cm) had significant impact on ENE (HR = 2.107). Minimal ETE particularly those with larger primary tumor (≥1 cm) may be still considered as a significant factor regarding the management of cervical LNs in patients with PTC.