Analysis of lymph node metastasis distribution patterns and dissection efficacy in thoracic esophageal cancer

To investigate the distribution patterns and dissection efficacy of lymph node metastasis in thoracic esophageal cancer, providing a theoretical basis for standardized lymphadenectomy during esophageal cancer surgery.

A total of 703 patients who underwent radical resection for thoracic esophageal cancer via the right thoracic approach at the Fourth Hospital of Hebei Medical University between January 2014 and March 2023 were analyzed. According to tumor location, patients were classified into upper, middle, and lower thoracic groups. Lymph nodes were categorized anatomically into three regions: upper mediastinum, lower mediastinum, and upper abdomen. Stratified analyses were performed according to tumor invasion depth (T stage) and histological differentiation grade. Metastasis rates and efficacy index (EI) values were calculated for each lymph node station to clarify correlations between tumor characteristics and nodal involvement and to assess the impact of metastatic stations on patient survival.

Overall metastasis rates to the upper mediastinal, lower mediastinal, and upper abdominal lymph nodes were 37.55%, 18.07%, and 23.33%, respectively. Among all stations, the right recurrent laryngeal nerve lymph nodes (Station 106recR) exhibited the highest metastasis rate (22.62%) and EI (11.22). Metastasis to lymph nodes along the hepatic artery (Station 8a), celiac axis (Station 9), and proximal splenic artery (Station 11p) was extremely low (≤0.85%). Stratified analysis showed that in upper and middle thoracic cancers, metastasis was most frequent at Station 106recR, with both the metastasis rates and EI increasing with greater tumor invasion invasion (T3-T4 vs. T1-T2) and poorer differentiation. For example, in upper thoracic cancer with T3-T4 poorly differentiated tumors, Station 106recR had a metastasis rate of 44.44% and an EI of 22.22. In lower thoracic cancers, perigastric lymph nodes (Stations 1-4) had the highest metastasis rate (24.71%) and EI (10.08). Among T1-T2 tumors, moderately-to-well differentiated cases metastasized predominantly to Station 106recR (7.69%, EI 5.13), whereas poorly differentiated tumors primarily involved the left gastric artery nodes (Station 7; 33.33%, EI 12.50). In T3-T4 poorly differentiated lower thoracic tumors, perigastric nodes showed the highest metastasis (59.46%, EI 22.31).

Lymph node metastasis in thoracic esophageal cancer exhibits distinct, site-specific patterns. Upper and middle thoracic tumors predominantly metastasize upward to recurrent laryngeal nerve nodes, whereas lower thoracic tumors primarily involve the perigastric region. The risk and extent of lymph node metastasis-including the number of involved nodes, nodal stations, and EI values-increase with deeper invasion and poorer differentiation. Although distant lymph node metastasis occurs frequently in advanced disease, an EI of zero indicates no survival benefit from extended lymphadenectomy. Surgical lymphadenectomy should therefore be individualized based on tumor location, invasion depth, differentiation, and nodal metastatic patterns.