A Prospective Trial on Optimal Extent of Lateral Neck Dissection in pN1 Papillary Thyroid Carcinoma

BACKGROUND: There is much controversy on the extent of lymph node dissection (LND) for papillary thyroid carcinoma (PTC) patients with lymph node metastasis (LNM) according to major guidelines. This study aims to explore the optimal extent of LND and discover a personalized and accurate surgical plan for pN1 PTC patients. METHODS: This prospective study included 550 patients with PTC who underwent initial surgery. For patients who were considered pN1a, LND of levels III and IV was completed. For patients who were considered LNM in levels III or IV, after taking 3-6 lymph nodes of level III for frozen pathological examination, if LNM was found, LND of levels II-IV was performed; otherwise, only levels III and IV were dissected, For patients who were considered to have LNM in level II, LND of levels II-V was performed. Statistical analysis was performed using SPSS software. RESULTS: 51.4% of patients with pN1a had postoperative pathologically confirmed occult LNM in levels III and IV. Among patients who underwent LND of levels II-IV due to positive lymph nodes in level III, 46.1% had occult LNM in level II. For patients with LNM in level II, the incidence of occult metastasis in level V was 20%. Only one patient presented with lymph node recurrence outside of the operative field. The proportion of patients with postoperative complications increased as the scope of dissection enlarged. CONCLUSION: Combined with the distribution of LNM and the number of subregions of LNM(n) in preoperative ultrasonography, it is suggested that the range of LND in the lateral neck of pN1 PTC should be n + 1/2 anatomical subregions.