Background/aims: Lymph nodes in patients with squamous cell carcinoma of the thoracic esophagus might be involved with metastases at cervical, mediastinal, and abdominal sites. The range of lymph node dissection is still controversial. The pattern of lymph node metastasis and factors that are correlated with lymph node metastasis affect the surgical procedure of lymph node dissection. The purpose of the present study was to explore the pattern of lymph node metastasis and factors that are correlated with lymph node metastasis in patients with esophageal cancer who underwent three-field lymphadenectomy.
Methods: Lymph node metastases in 230 patients who underwent radical esophagectomy with three-field lymphadenectomy were analyzed. The metastatic sites of lymph nodes were correlated with tumor location by chi-square test. Logistic regression was used to analyze clinicopathological factors related to lymph node metastasis.
Results: Lymph node metastases were found in 133 of the 230 patients (57.8%). The average number of resected lymph nodes was 25.3 +/- 11.4 (range 11-71). The proportions of lymph node metastases were 41.6, 19.44, and 8.3% in neck, thoracic mediastinum, and abdominal cavity, respectively, for patients with upper thoracic esophageal carcinomas, 33.3, 34.7, and 14%, respectively, in those with middle thoracic esophageal carcinomas, and 36.4, 34.1, and 43.2%, respectively, for patients with lower thoracic esophageal carcinomas. We did not observe any significant difference in lymph node metastatic rates among upper, middle, and lower thoracic carcinomas for cervical or thoracic nodes. The difference in lymph node metastatic rates for nodes in the abdominal cavity was significant among upper, middle, and lower thoracic carcinomas. The lower thoracic esophageal cancers were more likely to metastasize to the abdominal cavity than tumors at other thoracic sites. A logistic regression model showed that depth of tumor invasion and lymphatic vessel invasion were factors influencing lymph node metastases.
Conclusions: Based on our data, cervical and mediastinal node dissection should be performed independent of the tumor location. Abdominal node dissection should be conducted more vigorously for lower thoracic esophageal cancers than for cancers at other locations. Patients with deeper tumor invasion or lymphatic vessel invasion were more likely to develop lymph node metastases.