Role of Recurrent Laryngeal Nerve Lymph Node Dissection in Surgery of Early-Stage Esophageal Squamous Cell Carcinoma

Background: In esophageal cancer surgery, it is difficult to perform thorough dissection of lymph nodes along the recurrent laryngeal nerve (RLN-LN). However, there are limited data regarding the necessity of RLN-LN dissection in surgery for superficial esophageal squamous carcinoma (focused on T1b tumor) and its role in locoregional control and accurate nodal staging. Methods: Between 2001 and 2016, 567 patients with pT1N0 and 927 patients with cT1N0 squamous cell carcinoma were identified in a prospectively maintained, single institution esophagectomy registry. Sufficient or insufficient RLN-LN assessment group was defined by receiver operating characteristic curve analysis of the number of RLN-LN harvested. To mitigate bias, inverse probability weighting adjustment and several sensitivity analyses were performed. Results: In the pT1N0 cohort, patients with sufficient (≥ 4) harvested RLN-LNs showed significantly superior 5-year recurrence-free survival (89.1% versus 74.8%, log-rank P < 0.001). Patients with insufficient RLN-LN dissection mainly developed locoregional failure at the upper mediastinal or cervical area (87% of total recurred cases). The survival impact of sufficient RLN-LN dissection was more prominent in subsets of upper-middle thoracic tumors or with deep submucosal invasion. In the analysis on cT1N0 cohort, sufficient RLN-LN assessment conferred a 1.5-fold increase in the discovery of positive-nodal disease (19.4% versus 27.8%, P = 0.008). Conclusions: Adequate RLN-LN dissection during surgery may help reduce the risk of recurrence and enhance the accuracy of nodal staging in early-stage esophageal squamous cell carcinoma. Therefore, meticulous surgical evaluation for this region should not be underrated, particularly in the high-risk subset with lymph node metastasis. Graphic Abstract: [Figure not available: see fulltext.] VisualAbstract Graphical summary of key study findings. T wo cohorts (pT1 and cT1 ; both mainly comprised T1b) were analyzed for separate purposes; theformer controlled for pathologic stage was primarily analyzed in terms of survival and recurrence hazard, whereas the latter (controlled for clinical wasused for stage migration (and intention to treat analysis. Th e results show the significance of adequate bilateral RLN LN in the surgery for early stageESCC (particularly those with T1b)T1b), in terms of accurate nodal staging, effective nodal clearance, and reduced regional.