Aim: To determine the rate of abdominal lymph node metastasis after radical surgery for esophageal cancer and define the radiotherapy target area.
Methods: Of the 1593 patients who underwent R0 radical esophagectomy for thoracic esophageal squamous cell carcinoma (TE-SCC), 148 developed abdominal lymph node (LN) metastases within three years of surgery. During that time interval, patients were examined by various imaging methods (enhanced computer tomography, magnetic resonance imaging, and positron emission tomography-CT) at set time points. The emerging recurrence pattern, preferred sites for abdominal metastasis, and correlation with added clinical factors were carefully recorded, to permit for delineation of a target area for radiotherapy.
Results: We found postoperative metastatic abdominal LNs in 9.3% of the patients treated for esophageal cancer. Lesions in the upper, middle, and lower esophageal segments metastasized to abdominal LNs at 2.3%, 7.8%, and 26.6% (P < 0.0001), respectively. Of all cases, 4.8% had fewer than two affected LNs, while 20.1% had more than three metastatic LNs (P< 0.0001). The metastasis rates of negative and positive celiac LNs were 4.6% and 22.7%, respectively. Abdominal LN metastasis rates for the following LNs: 16a2 and 16a1 of para-aortic, celiac artery, posterior surface of the pancreatic head and common hepatic artery were 64.9%, 41.2%, 37.8%, 32.4%, and 20.9%, respectively. The overall rate of metastasis to these groups of LNs was 91.9%.
Conclusion: This study determined that stations 16a1 and 16a2 of the para-aortic, truncus coeliacus, posterior surface of the pancreatic head, and arteria hepatica communis lymph nodes were the preferred sites for abdominal LN metastasis, thus defining target areas for postoperative radiotherapy.