[Significance of subcarinal lymph node selective dissection in thoracic esophageal carcinoma]

Surgical resection remains the cornerstone of treatment for esophageal carcinoma. Mediastinal lymphadenectomy including subcarinal nodes has always been considered to be a reasonable extent, because of close anatomical relationship between subcarinal nodes and tracheobronchial tree. Metastatic involvement of subcarinal nodes alone is rare in esophageal carcinoma. In view of special anatomical features of subcarinal lymph nodes, it is worth exploring and discussing whether or not subcarinal lymph nodes dissection shall be routinely performed for thoracic esophageal carcinoma.

The data from a cohort of 676 patients with thoracic esophagus carcinoma who underwent esophagectomy with lymphadenectomy were analyzed retrospectively with respect to the impact of subcarinal lymph nodes dissection or non-dissection on the incidence of postoperative complications and patient survival.

The rate of subcarinal lymph nodes metastasis was 10.4%. The metastasis rates in upper, middle and lower esophageal carcinoma were 0%, 13.2% and 6.8% respectively (P = 0.001); for Tis, T1, T2, T3 and T4, they were 0%, 0%, 6.5%, 13.3% and 28.6% respectively (P = 0.008). The overall incidence of postoperative complications with and without subcarinal lymph nodes dissection was 36.8% versus 26.6% (P = 0.013). And the incidence of pulmonary complications were 22.2% versus 14.1% (P = 0.020). Survival analysis showed that: the 5-year survival rates were 50.9% versus 62.8% in the groups A and B of N0 patients (P = 0.083); 14.7% versus 29.3% in N1 patients (P = 0.112). In the group with metastasis of subcarinal lymph nodes, the 5-year survival rate was 22.6% versus 31.7% in those without metastasis (P = 0.142).

It may be unnecessary to dissect the subcarinal lymph nodes routinely for upper thoracic esophageal carcinoma. Elective subcarinal lymph nodes dissection can be planned for middle, lower, T3 or T4 thoracic esophageal carcinoma, or highly suspected subcarinal metastasis based on radiological imaging.