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 > or =10 mm 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=203). 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.