Macroscopic lymph-node involvement and neck dissection predict lymph-node recurrence in papillary thyroid carcinoma

Objective: Whether lymph-node dissection (LND) influences the lymph-node recurrence (LNR) risk in patients with papillary thyroid cancer remains controversial. The prognostic impact of macroscopic and microscopic lymph-node involvement at diagnosis is also an unresolved issue. A retrospective study was conducted to assess the influence of various LND procedures and to search for LNR risk factors. Methods: Overall 545 patients without distant metastases prior to surgery and main tumour >= 10 min were included. A total thyroidectomy was performed in all patients with either no LND (Group 1, n= 161), bilateral LND of the central and lateral compartments (Group 2, n = 181) or all other dissection modalities (Group 3, n = 2 03). Post-operative radioiodine was given to 496 (91%) patients. The 10-year cumulative probability of LNR was assessed and a prognostic study using multivariate analysis was performed. Results: Macroscopic lymph-node metastases were present in 118 patients, 57 diagnosed before surgery and 61 only at surgery (including 81% in the central compartment). Overall, the 10-year cumulative probability of LNR was 7%. Macroscopic lymph-node metastases (P=0.001), extra-thyroidal invasion (P=0.017) and male gender (P=0.05) were independent risk factors, while bilateral LND of the central and lateral compartments was protective (P=0.028). In patients with macroscopic lymph-node metastases, the 10-year probability was lower in Group 2 than in Group 3 (10%, vs 30%, P < 0.01). In patients without macroscopic lymph-node metastases (n = 427), no significant differences were observed between the three LND groups. Conclusions: Patients with macroscopic, but not microscopic, lymph-node involvement have a major LNR risk and need an optimal LND at primary surgery.