Evaluation of subcarinal lymph node dissection and metastasis in transmediastinal radical esophagectomy

BACKGROUND: The aim of the present study was to evaluate subcarinal lymph node dissection in transmediastinal radical esophagectomy and subcarinal lymph node metastasis in patients with esophageal cancer. METHODS: Three hundred and twenty-three patients with primary esophageal cancer who underwent transmediastinal or transthoracic esophagectomy with radical two- or three-field lymph node dissection were retrospectively investigated. The clinicopathological characteristics of patients with subcarinal lymph node metastasis were analyzed in detail. RESULTS: The median of dissected subcarinal lymph nodes in transmediastinal and transthoracic esophagectomy groups was 6 and 7, respectively, and there was no significant difference between the two groups (p = 0.12). Of all patients, 26 (8.0%) were pathologically diagnosed as positive for subcarinal lymph node metastasis, whereas only 7 (26.9%) of those with metastasis were preoperatively diagnosed as positive. In addition, all patients with subcarinal lymph node metastasis had other non-subcarinal lymph node metastasis. By univariate analysis, subcarinal lymph node metastasis was found in larger (≥ 30 mm) and deeper (T3/T4a) primary lesions (p = 0.02 and 0.02, respectively), but it was not found in 49 patients with the primary lesion located in the upper thoracic esophagus. CONCLUSIONS: Subcarinal lymph nodes can be dissected in transmediastinal esophagectomy, almost equivalent to transthoracic esophagectomy. The tumor size, depth, and location may be predictive factors for subcarinal lymph node metastasis.