The patterns of lymph node metastasis in adenocarcinoma of esophagogastric junction : a reference for target volume delineation in radical radiotherapy

Abstract

Objective To analyze the patterns and distribution of lymph node metastasis in patients with adenocarcinoma of the esophagogastric junction(AEG). Methods The pathological data of 393 patients with AEG from 2006 to 2009 were analyzed. The patterns and distribution of lymph node metastasis were analyzed in patients with different Siewert subtypes, depths of tumor invasion, and maximum diameters of the tumor, and the high-risk lymphatic drainage areas were investigated. Between-group comparison was performed by χ2 test. Results The metastatic rate and ratio of abdominal lymph nodes in AEG were 69. 2% and 31. 31%, respectively. The incidence rates of lymph node metastasis in the cardia, lesser curvature, left gastric artery, splenic artery, splenic hilum, mesenteric root, and abdominal aorta were the highest. The metastatic rate and ratio of mediastinal lymph nodes were 16.4% and 8.3%, respectively. The incidence rates of lymph node metastasis in the lower paraesophageal, esophageal hiatus, and superior diaphragmatic areas were the highest. Compared with Siewert type Ⅱ and type Ⅲ AEG, Siewert type I AEG had a significantly higher mediastinal lymph node metastatic rate(P = 0. 003)and a significantly lower abdominal lymph node metastatic ratio(P=0. 002).The metastatic ratios of lymph nodes in multiple abdominal regions were higher in patients with stage T3+T4 AEG and a maximum tumor diameter of cm than in the control group, while the metastatic ratios of mediastinal lymph nodes in groups with different maximum tumor diameters were similar. The metastatic ratios of lymph nodes in the greater curvature, hepatoduodenal ligament, and inferior diaphragmatic areas were lower than 10% in all groups. Conclusions In radiotherapy for AEG, the abdominal high-risk lymphatic drainage areas involve the cardia, lesser curvature, left gastric artery, splenic artery, splenic hilum, mesenteric root, and abdominal aorta, while the mediastinal high-risk lymphatic drainage areas involve the lower paraesophageal, esophageal hiatus, and superior diaphragmatic areas. In addition, the personalized target volume design should be based on the patterns of lymph node metastasis with different Siewert subtypes and clinical pathological characteristics. Key words: Esophagogastric junction neoplasm/radiotherapy; Target delineation; Lymph node metastasis