Adenocarcinoma of the esophagogastric junction: the pattern of metastatic lymph node dissemination as a rationale for elective lymphatic target volume definition.

PURPOSE: Regional nodal metastasis after neoadjuvant chemoradiation of adenocarcinoma of the esophagogastric junction (AEG) predicts survival. We aimed to clarify the lymph node (LN) distribution of AEG according to location of the tumor mass and invasion of neighboring areas for the selection of radiotherapy planning target volume (PTV) margins. METHODS AND MATERIALS: Patterns of regional spread were analyzed in pathology reports of 326 patients patients with AEG who had undergone primary resection, with > or = 15 lymph nodes examined. Tumors were classified into AEG types based on endoscopy and pathology reports. Fisher's exact test was used to compare nodal disease and tumor characteristics. Pulmonary dose-volume histograms were tested in 8 patients.
RESULTS: Nodes were positive in 81% of T2 to T4 tumors. Type of AEG, tumor size, lymphovascular invasion, and grading significantly influenced nodal distribution. We found that marked esophageal invasion of AEG II/III significantly correlated with paraesophageal nodal disease, and T3 to T4 AEG II/III had a significant rate of splenic hilum/artery nodes. Middle and lower paraesophageal nodes should be treated in T2 to T4 AEG I and AEG II with > or = 15 mm involvement above the Z-line, and T3 to T4 AEG II. The splenic hilum and artery nodes can be spared in T2 AEG tumors, especially Type I tumors. The influence of paraesophageal nodal treatment on the risk of postoperative pulmonary complications can be estimated from dose-volume histograms.
CONCLUSIONS: Accurate pretherapeutic staging predicts the risk of subclinical nodal disease and should be used to select the appropriate radiotherapeutic PTV. Careful selection of the PTV can be used to maximize the therapeutic window in multimodal therapy for AEG.