Current and proposed treatment strategies for Siewert type II adenocarcinoma of the esophagogastric junction

(Background) Incidence of adenocarcinoma of the esophagogastric junction (AEG) is increasing in Japan as well as Western Country. However, there is no consensus on treatment strategy. The purpose of this study was to determine the optimal range of resection and lymph node dissection for Siewert type II AEG and to develop a strategy for treatment that includes adjuvant therapy to improve the survival rate. (Methods)We retrospectively investigate 88 cases of advanced AEG in patients who underwent surgery with lymph node dissection with 52 cases of superficial AEG, 23 of whom underwent endoscopic treatment (endoscopic mucosal resection [EMR] or endoscopic submucosal dissection [ESD]), and 29 of whom underwent surgery with lymph node dissection. (Results) The optimal lymph nodes to resect for advanced AEG were No. 110, 1, 2, 3, 7,11. According to area of actual lymph node metastasis, lymphadenectomy of lymph nodes 1, 2, 3, 7, and 11 was sufficient to improve survival of patients with superficial AEG. The 5-year overall survival rates were 88% for patients treated with ESD, 78% for those with superficial AEG who under-went surgery, and 24% for those with advanced AEG (p = 0.011). There were no differences in survival between patients who received postoperative adjuvant therapy with S-1 for advanced AEG and those who received surgery alone (p = 0.5192).(Conclusion) Although surgical procedures of superficial and locally advanced AEG are standardized, the role of adjuvant therapy for AEG is still controversial. We recommend nab-paclitaxel plus radiotherapy for advanced AEG as neoadjuvant therapy.