Significance of dissection in each regional lymph-node station of esophageal cancer based on efficacy index and recurrence patterns after curative esophagectomy

Background The optimal extent of lymph-node (LN) dissection in esophageal cancer has not been established. Although the frequency and patterns of recurrence in each regional LN station after radical dissection are important in determining the regional LNs of thoracic esophageal cancer to be routinely dissected, this information has not been investigated sufficiently. We studied the significance of dissection at each LN station based on their recurrence patterns. Methods Six hundred and twelve patients with esophageal cancer who underwent curative esophagectomy were studied. The incidence and pattern of recurrence (systemic or non-systemic) at each regional LN station were analyzed. To compare the significance of dissection among regional LNs, the efficacy index (EI) was also calculated. Results Regional LN recurrence was diagnosed in 101 (16.5%) patients. Among the regional LNs, recurrent laryngeal nerve, paraesophageal, and perigastric LNs showed higher EIs (3.1-6.7). Pretracheal and posterior thoracic para-aortic LNs showed low EIs (0-0.2). Supraclavicular LNs had moderate EIs (1.7-2.0). The recurrence rate was highest in the pretracheal LN, followed by the supraclavicular LNs. The majority (81.8%) of the pretracheal LN had a systemic recurrence, while about half (right: 60.0%, left: 43.8%) of the supraclavicular LNs had a systemic recurrence. Conclusion Due to the high incidence of systemic recurrence or low EI for pretracheal and posterior thoracic para-aortic LNs, we suggest that these LN stations be regarded as non-regional LNs and be excluded from routine dissection. Supraclavicular LNs may also be excluded from routinely dissected stations.