The lymph node yield in the initial lateral neck dissection predicts recurrence in the lateral neck of papillary thyroid carcinoma: a revision surgery cohort study

This study aimed to evaluate the relationship between lateral lymph node yield (LLNY) and the ratio of lateral positive lymph nodes to lymph node yield (LPLR) from initial lateral neck dissection (LND) in patients with papillary thyroid carcinoma (PTC), as well as the risk of recurrence in patients undergoing LND reoperations. METHODS: This retrospective cohort study enrolled patients with PTC who underwent revision LND between 1 January 2012, and 31 December 2021. The initial and revised clinical data were retrieved. Patient demographics, clinicopathological features, clinical records, and follow-up information were also reviewed. LLNY and LPLR were determined during the initial LND. RESULTS: In total, 156 patients with PTC were included in this study, with a median follow-up of 36.5 months; 107 had recurrent lateral neck disease. The optimal LLNY and LPLR cutoff values for recurrent/persistent disease were 24.5 and 32.74%, respectively. The high-risk group (LLNY<25) had the lowest recurrence-free survival rate compared with to moderate-risk group (LLNY≥25, LPLR≥32.74%) and low-risk group (LLNY≥25, LPLR<32.74%) (P<0.001). The moderate-risk group had lower recurrence-free survival than the low-risk group. Multivariate analysis revealed that an LLNY less than 25 in the initial LND was an independent risk factor for recurrence/persistence of lateral neck (P<0.001). CONCLUSIONS: This study identified that LLNY and LPLR were associated with recurrence/persistence in PTC patients at the time of revision surgery was performed.