Objective: To investigate the characteristics of lymphatic metastasis in different types of adenocarcinoma of the esophagogastric junction (AEG) and provide guidance for surgical approach adoption.
Methods: Clinical data of 228 patients with AEG undergoing surgery were analyzed retrospectively. According to Siewert classification, there were 9 cases of type I (3.9%) who all underwent left thoracoabdominal approach procedures. A total of 121 patients belonged to type II (53.1%), of whom 12 underwent left transthoracic approach, 48 left thoracoabdominal approach, and 61 transabdominal approach. Ninety-eight patients belonged to type III (43%), of whom 22 underwent left thoracoabdominal approach procedures and 76 transabdominal. The pattern of lymph node metastasis was analyzed and the association between surgical approach and oncological clearance was examined.
Results: The resection margin was positive in 20(8.8%) patients, including 10 with type II (8.3%) and 10 with type III (10.2%), and the difference was not statistically significant (P>0.05). The rate of positive resection margin was 12.4%(17/137) in the transabdominal group and 16.7%(2/12) in the left transthoracic group, both significantly higher than the left thoracoabdominal group (1.1%, 1/88) (both P<0.05). Lymph node metastasis was found in 159(69.7%) patients. The metastasis was found in 4 of 9 patients with type I cancer and two were thoracic metastasis, no metastasis was found in the upper mediastinum. For type II cancer, the rate of lymph node metastasis was 66.9%(81/121), including thoracic metastasis ( n=32, 26.4%) and abdominal metastasis (n=81, 66.9%). For type III cancer, the rate of lymph node metastasis was 66.9%(81/121), including thoracic metastasis (n=15, 15.3%) and abdominal metastasis (n=69, 70.4%).
Conclusions: For type I AEG, left thoracoabdominal approach should be used because the pattern of lymph node metastasis is similar to that of the distal esophageal carcinoma. For type II , left thoracoabdominal approach should be used to ensure adequate resection of the tumor and clearance of lymph node in the lower esophagus and upper mediastinum because of high rate of intrathoracic lymph node metastasis. For type III cancer, transabdominal incision offers better benefit with less impact on respiratory function. However, thoracic incision should be used to ensure adequate clearance for tumors of larger size and significant external invasion.