Excellent Prognosis of Central Lymph Node Recurrence-Free Survival for cN0M0 Papillary Thyroid Carcinoma Patients Who Underwent Routine Prophylactic Central Node Dissection

INTRODUCTION: In Japan, prophylactic central node dissection (p-CND) for papillary thyroid carcinoma (PTC) has been routinely performed in many institutions, including ours (Kuma Hospital, Japan). We evaluated the recurrence to a central lymph node in patients with cN0M0 PTC who underwent routine p-CND. MATERIALS AND METHODS: We enrolled 4301 patients with cN0M0 PTC who underwent an initial surgery between 1987 and 2005 (median age 51 years). The postoperative follow-up periods ranged from 4 to 362 months (median 164 months). Only 15 patients underwent radioactive iodine (RAI) ablation (≥30 mCi) after total or near total thyroidectomy. RESULTS: Of the 4301 patients with N0M0 PTC who underwent p-CND, 2548 (59%) were diagnosed as pN1a on postoperative pathological examination. To date, only 52 cases (1.2%) showed recurrence to a central lymph node. The 10-year and 20-year central node recurrence-free survival rates were excellent at 99.1 and 98.2%, respectively. On multivariate analysis, age ≥55 years, significant extrathyroid extension, tumor size >2 cm, and ≥5 pathologically confirmed central node metastases (but not the presence of central node metastasis) independently affected central node recurrence. CONCLUSIONS: Under the situation of routine p-CND, the central node recurrence-free survival of cN0M0 PTC is excellent. However, future studies, including double-arm studies from Japan, should examine whether the omission of p-CND cN0M0 PTC is appropriate without RAI ablation in consideration of various factors, including the pros and cons of p-CND.