The value of enhanced CT scanning for predicting lymph node metastasis along the right recurrent laryngeal nerve in esophageal squamous cell carcinoma

Background: The right recurrent laryngeal nerve (RRLN) is the region most prone to lymph node metastasis in esophageal squamous cell carcinoma (ESCC). Nodal involvement may be underestimated by traditional imaging prediction criteria, such as a short axis diameter of 10 mm. The purpose of this study was to determine a more accurate imaging criterion to guide clinical treatment strategy selection. Methods: The clinical data of 307 patients with thoracic ESCC who underwent surgery at Shanghai Chest Hospital between January 2018 and December 2018 were retrospectively analyzed. Utilizing 1-mm layer thickness enhanced computed tomography (CT), the RRLN lymph node short diameter (LNSD) size was measured. Univariate and multivariate analyses were performed to determine the risk factors for lymph node metastasis along the RRLN. Results: In our study, RRLN lymph node metastasis occurred in 60 (19.5%) patients and general lymph node metastasis occurred in 150 (48.9%) patients. Of the resected lymph nodes along the RRLN, 14.5% (121/832) were positive. Multivariate analysis identified LNSD [odds ratio (OR), 1.236] as an independent risk factor for RRLN lymph node metastasis. In CT evaluation, a short diameter of 6.5 mm in the RRLN lymph nodes is a critical predictor of metastasis at this site (sensitivity =50%, specificity =83.4%) and a larger short diameter was associated with a higher risk of metastasis (P<0.001). Conclusions: A 6.5 mm cutoff in LNSD can be applied to clinically predict lymph node metastasis in the RRLN region for patients with ESCC.