Prognostic significance of the number of metastatic lymph nodes to stratify the risk of recurrence.

Abstract

BACKGROUND: Prophylactic dissection facilitates identification of central lymph

node (LN) metastasis in patients with papillary thyroid cancer (PTC). Because

most staging systems do not stratify risks by the number of LN metastases,

postoperative treatments vary among different institutions. Therefore we

investigated the significance of number of LN metastases in risk stratification

for recurrence in PTC. MATERIAL AND METHODS: A retrospective review was performed

for 3,305 patients who had undergone thyroidectomy at Ajou University Hospital. A

total of 2,462 patients (73.5 %) underwent total thyroidectomy, and another 3,152

(94.1 %) underwent central LN dissection. Lateral cervical LN dissection had been

performed in 420 patients (12.5 %). RESULTS: There were 115 patients with

recurrence (3.4 %). Recurrence-free rates were 94.6 % at 5 years and 89.4 % at 10

years. On univariate analysis, prognostic factors for recurrence were extent of

thyroidectomy, tumor size, capsular invasion, T stage, N stage, number of LN

metastasis, TNM stage, and radioactive iodine (RAI) therapy. On multivariate

analysis, number of LN metastasis and N stage were significant prognostic factors

for recurrence. Recurrence-free rate was significantly different between patients

with 0-1 LN and those with 2 or more LN. CONCLUSIONS: Number of metastatic LN was

a significant prognostic factor, in addition to the N stage. Therefore, number of

metastatic LN must be considered for postoperative staging system to tailor

treatment and follow-up recommendations. In addition, patients with >/=2

metastatic LN may benefit from total thyroidectomy and RAI therapy with

postoperative follow-up with serum thyroglobulin.