Predictive value of nodal metastases on local recurrence in the management of differentiated thyroid cancer. Retrospective clinical study.

Background: The significance of nodal metastases, very common in papillary thyroid cancer, and the role of lymph node dissection in the neoplasm management, are still controversial. The impact of lymph node involvement on local recurrence and long-term survival remains subject of active research. With the aim to better analyze the predictive value of lymph node involvement on recurrence and survival, we investigated the clinico-pathological patterns of local relapse following total thyroidectomy associated with lymph node dissection, for clinical nodal metastases papillary thyroid cancer, in order to identify the preferred surgical treatment. Methods. Clinical records, between January 2000 and December 2006, of 69 patients undergoing total thyroidectomy associated with selective lymph node dissection for clinical nodal metastases papillary thyroid cancer, were retrospectively evaluated. Radioiodine ablation, followed by Thyroid Stimulating Hormone suppression therapy was recommended in every case. In patients with loco regional lymph nodal recurrence, a repeated lymph node dissection was carried out. The data were compared with those following total thyroidectomy not associated with lymph node dissection in 210 papillary thyroid cancer patients without lymph node involvement, at preoperative ultrasonography and intra operative inspection. Results: Incidence of permanent hypoparathyroidism (iPTH < 10 pg/ml) and permanent monolateral vocal fold paralysis were respectively 1.4 % (1/69) and 1.4% (1/69), similar to those reported after total thyroidectomy "alone". The rate of loco regional recurrence, with positive cervical lymph nodes, following 8 year follow-up, was 34.7% (24/69), higher than that reported in patients without nodal metastases (4.2%). A repeated lymph node dissection was carried out without significant complications. Conclusions: Nodal metastases are a predictor of local recurrence, and a higher rate of lymph node involvement is expected after therapeutic lymph node dissection associated with total thyroidectomy. The prognostic significance of nodal metastases on long-term survival remains unclear, and more prospective randomized trials are requested to better evaluate the benefits of different therapeutic approaches