Significance of regions of abdominal lymph node metastasis for target volume delineation in postoperative radiotherapy for patients with recurrent esophageal carcinoma after radical surgery

Abstract

Objective To analyze the regions of abdominal lymph node metastasis in recurrent thoracic esophageal squamous cell carcinoma (TE-SCC) after radical surgery, and to guide the design of target volume in postoperative adjuvant radiotherapy. Methods Patients with TE-SCC who were admitted to our hospital from February 2005 to April 2013 were enrolled as subjects. All patients were diagnosed with abdominal lymph node metastasis by imaging after R0 radical surgery. The exact regions of abdominal lymph node metastasis were classified according to the 7th edition of American Joint Committee on Cancer (AJCC) TNM staging system for gastric cancer, and then retrospectively analyzed. The difference of two group was analyzed by χ2 test. Results Among the 1593 eligible patients, 148(9.3%) were diagnosed with abdominal lymph node metastasis after surgery. In the 148 patients, the abdominal lymph node metastasis rates in the upper, middle, and lower thoracic esophagus were 2.3%, 7.8%, and 26.6%, respectively (P=0.000); the incidence rates of pathological stages T1/2 and T3/4 were 8.7% and 9.5%, respectively (P=0.601); the incidence rates of 0-2 and ≥3 metastatic lymph nodes in postoperative pathological examination were 4.8% and 20.1%, respectively (P=0.000). The abdominal lymph node metastasis rate was the highest in the para-aortic lymph node (16a2), followed by para-aortic lymph node (16a1) and the lymph nodes around the celiac trunk, posterior area of the pancreatic head, and common hepatic artery (64.9%, 41.2%, 37.8%, 32.4%, and 20.9%), yielding an overall metastasis rate of 91.9%. Conclusions The major regions of abdominal lymph node metastasis in esophageal carcinoma after radical surgery include para-aortic lymph nodes (16a2 and 16a1) and the lymph nodes around the celiac trunk, posterior area of the pancreatic head, and common hepatic artery. These regions are the abdominal target volumes of postoperative adjuvant radiotherapy. Key words: Esophageal neoplasms/surgery; Lymph node metastasis; Esophageal neoplasms/radiotherapy; Target