P-0019 Propotion of Early Gastric Cancer is Indirectly Correlated with Survival after Radical Surgery for Gastric Cancer at any Resectable Stage

Abstract

ABSTRACT Introduction Geographic variability in prognosis of gastric cancer (GC) is well documented, as in Japan series higher survival rates were reported when compared with Western patients at the same stage of disease. We suppose any resectable stage (I-III stages) of GC can be subdivided into two subcategories – without and with synchronous occult distant metastases (SOcDM). Unfortunately today we are unable to establish the existence of SOcDM. That is why we categorize both subcategories in one stage, but really they are distinct “stages”. We postulate that higher proportion of early gastric cancer (EGC) in a large cohort of patients is correlated with lower percentage of SOcDM in cases of resectable GC. Methods We investigated our own data and papers written by authors of Japan and Western Europe studying EGC, survival after D2 gastrectomy for GC, and analyzing the frequency of synchronous obvious distant metastases (SObDM) published in English from 1992 to 2011 which were available to us and were not purposefully chosen. We calculated the frequency of SOcDM by the formula Foc= kFob, where Foc is the frequency of SOcDM, Fob is the frequency of SObDM, k is constant. Arithmetically we found k constant to be roughly 2. Results We determined that in Japan: 1) the proportion of EGC among all GC cases is higher (mean, 48% versus 17%, P Conclusion This is a new phenomenon being one of the independent powerful factors that impose on survival of patients with resectable GC. Difference in survival rates after RS for GC between Japan and Western Europe is to a great extent related to this phenomenon.