Central Neck Dissection in Papillary Thyroid Carcinoma: Benefits and Doubts in the Era of Thyroid Lobectomy

Introduction: Surgery is still the main line of treatment for papillary thyroid cancer (PTC) with a current trend for de-intensified treatment based on an excellent prognosis. The role of a routine prophylactic central neck dissection (PCND) is still debated as its impact on oncologic outcomes has never been cleared by a randomized clinical trial. In this study, we aimed to report our long-standing experience in PCND and its potential contemporary role in the treatment of PTC. Methods: A retrospective institutional review was performed on all patients who underwent operation for PTC including PCND between 1998 and 2021. The primary outcomes were the rate of central lymph node metastases (CLNMs), cancer recurrence and incidence of complications. Survivals were analyzed using the Kaplan-Meier estimator and Cox proportional hazard models. Results: A total of 657 patients were included in this study with a median follow-up of 78 months (48-114 months). Two hundred and one patients presented occult CLNMs (30.6%). The presence of a pathological node represented the unique reason for a completion thyroidectomy and I131 therapy in 12.5% of the population. Age lower than 55 years, microscopic or macroscopic extra-thyroid extension (ETE) and multifocality were independent factors predicting CLNMs. The rate of recurrence in the whole population was 2.7% (18 patients). Five-year and ten-year disease-free survival (DFS) was 96.5% (94.7-97.7) and 93.3% (90.3-95.5), respectively. Two patients relapsed in the central neck compartment (0.3%). Age (>55 years), pathological staging (pT) and extranodal extension (ENE) were independent factors associated with a worse DFS. The rate of temporary and permanent vocal fold palsy was 12.8% and 1.8%, respectively, and did not depend on the type of surgical procedure performed. Hypoparathyroidism was temporary in 42.2% and permanent in 11.9% of the patients. A sub-analysis upon cT1b-T2 patients treated primarily with thyroid lobectomy and ipsilateral PCND demonstrated a 2.6% rate of permanent hypoparathyroidism. Conclusions: PCND allows for a high disease-free survival and a proper selection of patients needing adjuvant treatment, in particular, those treated with a unilateral procedure. On the other hand, bilateral approach is burdened by a not-neglectable rate of permanent hypoparathyroidism.