Prognostic values of clinical lymph node metastasis and macroscopic extrathyroid extension in papillary thyroid carcinoma.

In papillary thyroid carcinoma (PTC), macroscopic extrathyroid extension (Ex) and clinical node metastasis (N) are prominent prognostic factors. Ex is divided into two grades in the UICC TNM classification: minimal and massive Ex. Massive Ex significantly affects patients' prognoses, whereas minimal Ex has little prognostic value. N is also divided into two grades in the TNM classification: N1a and N1b, depending on the location of metastasis, with N1b graded higher than N1a. However, massive Ex and/or N-positive PTC includes patients with a wide range of biological characteristics and prognoses, depending on their degrees of Ex and N. Other clinicopathological features such as age, gender, and tumor size also influence the prognosis. In evaluations of the biological characteristics of PTC patients with Ex and/or N, we should consider the degrees and relationships of Ex and N with other clinicopathological features.