Abstract
Recently in Japan more than 40% of gastric cancers, including mucosal and submucosal carcinoma, have been detected at an early stage. Since data of the nationwide registry show a significantly lower rate (2.1%) of metastasis to lymph nodes of mucosal tumors, limited surgery is recommended. In order to establish criteria for selecting rational surgery for early gastric cancer, we conducted a study of lymph flow draining from stomach and metastatic route of perigastric lymph node.Analysis of the relationship between lymph mode metastasis and clinicopathological findings led to our new policy of surgical treatment for early gastric cancer. In our study, lymph node metastasis was not observed in the following cases: 1) mucosal cancer with elevation of less than 20mm among differentiated adenocarcinomas, 2) mucosal cancer with depression of less than 10mm, 3) submucosal cancer (sm-1) of less than 10 mm. In these cases, it is possible for rational limited surgery to be performed, with curability for early gastric cancer. Conversely, submucosal massive cancer (sm-2) has not only lymph vessel permeation but also nodal metastasis. Thus, limited surgry should not be carried out in submucosal cancer. As another limited procedure, a functional preserving operation, pylorus-preserving gastrectomy (PPG), should be applied to cases of early gastric cancer occurring in the middle third of the stomach. PPG should be considered a physiologically advantageous procedure. In selecting limited surgery, it is important to know to what extent we can make an accurate preoperative diagnosis of depth of cancer invasion or lesion size. The decision should be made taking into consideration the macroscopic findings, histological type and tumor size.
