82 Kwon SJ pathogenetic origins. Dolan et al.(33) reported a similarity in the etiology, epidemiology and clinicopathological features between an adenocarcinoma of lower esophagus and cardia. These authors re- ported that these two carcinomas should be classified as the same disease entity. According to large-scale studies conducted on 1,002 cases of the EG junction carcinoma, Rüdiger Siewert et al.(34) re- ported that Type I (tumors with the center located from 5 cm to 1 cm above the EG junction) formed a specific category that should be considered as a lower esophageal cancer and most of these cases occurred in the Barrett’s esophagus, which are the sites of intestinal dysplasia of the lower esophagus formed due to the EG regurgita- tion. In contrast, in Type II cases (tumors with the center located 1 cm above to 2 cm below the EG junction), the intestinal dysplasia formed in only 10% in the lower esophagus. In patients with Type III (tumors with the center located from 2 cm to 5 cm below the EG junction), the incidence of intestinal dysplasia was very low. Accordingly, there is great discrepancy between Type I cases. In other words, a Type II tumor is closer to gastric cancer at the prox- imal sites than a lower esophageal adenocarcinoma. In addition, according to studies on the lymphatic circulation, the lymphatic ducts originating from the lower esophagus bilaterally progress, i.e. the mediastinum superiorly and the celiac axis inferiorly. In cases of Type II and III, most lymphatic ducts progress to the celiac axis. For this reason, there is a difference in the pattern of lymph node metastasis between Types II and I tumors, which is also similar to Type III. In cases of Type II tumor, the esophagectomy has not improved the survival rate compared to an extensive gastrectomy. According to Kusano et al.,(35) the incidence of an EG junction carcinoma (Siewert Type II) was 10% in patients with progressive gastric cancer who had been treated surgically at the National Can- cer Center of Japan from 2001 to 2005 and the incidence of Siewert Type I was approximately 1%. According to studies comparing the characteristics of gastric cancer between Asians and Caucasians,(36) the incidence of an EG junction carcinoma was 0.4%, which is much lower than the 18% observed in Caucasians. In addition, fol- lowing the classification of an EG junction carcinoma into Siwert Types I and II, there were almost no cases of Type I in Koreans.(37) The incidence of upper gastric 1/3 cancer steeply increased sharply to 12.5% up to 1992. Since then, its increasing rate has been re- duced markedly and showed a greatly different tendency compared to the higher increasing rate observed in Caucasians.(38) According to the staging system on the seventh edition of the UICC TNM, cases in whom the central region of carcinoma was located within 5 cm superior and inferior to the EG junction and then invaded the EG junction, were classified based on the classification system for esophageal cancer. To evaluate the validity of the changes in this classification system, 496 cases of an EG junction carcinoma were classified based on the classification system of esophageal cancer in the seventh edition at the Seoul National University Hospital. This was followed by an analysis of the difference in the survival rate between the stages. The survival rate was similar in stage I (n=230) and stage II (n=116) (P=0.948), but there was a significant differ- ence in the survival rate between stages III (n=150) and II (P ＜0.001) and between stages III and I (P＜0.001). A comparative analysis of the survival rate between the TNM stages after the same patient group was classified based on the TNM staging revealed a difference in the survival rate between stage I (n=241) and stage II (n=125) at a moderate degree of statistical significance (P=0.089). In addition, there was a significant difference in the survival rate be- tween stages III (n=130) and II (P＜0.001) and that between stages III and I (P＜0.001). This suggests that the classification system for gastric cancer rather than the classification system for esophageal cancer reflects the difference in the survival rate between the TNM stages. One study examined the survival rates between the TNM stages in 4,027 cases of gastric cancer located more than 5 cm distal to the EG junction and 496 cases of the EG junction carcinoma. A comparison of the survival rate between the TNM stages in cases of the EG junction carcinoma, which had been classified based on the classification system for esophageal cancer and that for gastric cancer between the TNM stages, revealed a significant difference in the survival rate in stage II patients (P=0.021). Nevertheless, there was no significant difference in the survival rate between all the TNM stages (stage I, stage II and stage III) in cases of the EG junction carcinoma, which had been classified based on the classi- fication system for esophageal cancer and gastric cancers occurring at other sites. This suggests that the current revisions might fulfill the classification system for both cancers at distal and proximal sites. Based on these results, there is a higher degree of differences for EG junction carcinomas based on the classification system for gastric cancer rather than the classification system for esophageal cancer (not pressed). The Japanese Society for Gastric Cancer de- fined carcinomas located within 2 cm superiorly and inferiorly to the EG junction as EG junction cancer in collaboration with the Japanese Society for Esophageal Cancer.(39) Controversial opinions exist regarding the treatment modalities for cases of EG junction cancer. Currently, there is some consensus that the optimal treat- ment modalities should be selected based on the distance of tumor invasion to the stomach or esophagus rather than the location of