Effectiveness of lymphadenectomy along the thoracic duct for radical esophagectomy.

Background: There has been much debate on whether to perform TD resection in radical esophagectomy for esophageal cancer from the perspectives of metastatic rate, effect on postoperative hemodynamics, and other factors. The objective of this study was to determine whether TDLN dissection contributes to improved prognosis.

Methods: This study involved 1211 patients who underwent D2/D3 dissection with TD resection for thoracic esophageal cancer between 1984 and 2020. The lymph nodes along the TD were defined as TDLNs and the remaining No. 112 nodes as non-TDLNs. The metastatic rate in TDLNs and non-TDLNs and their outcomes were compared with those of other thoracic lymph nodes. Correlation with the invasion depth of the main lesion was also analyzed (T0-2 545 patients, T3-4 666 patients).

Results: The metastatic rates in TDLNs/non-TDLNs in all patients were 7.3%/7.5%, respectively, while those in T0-2 were 2.2%/3.9%, and those in T3-4 were 11.5%/10.6%, with both having higher rates in advanced cases. The efficacy index (EI) for lymphadenectomy in T3-4 was 2.94 for TDLNs and 3.44 for non-TDLNs, with no significant difference. The metastatic rate in TDLNs by tumor site was as follows: Ut/Mt/Lt = 1.1/2.4/2.4% (T0-2) and 7.7/14.5/8.4% (T3-4), being especially high (~ 15%) in patients with advanced cases in Mt region. The EI was comparable or higher for TDLNs compared with other group-2 (Mt/Lt) and group-3 (Ut) regional lymph nodes, regardless of site.

Conclusions: The significance of TD resection was low in T0-2 due to the low metastatic rate but became evident in cases with invasion depth of T3-4. TDLN resection was at least as effective as dissection of other group-2 or -3 lymph nodes, including No. 112 nodes.