We are living in an era of unprecedented rapid change for gastric cancer. For a long time it was the commonest cancer, but its occurrence started to decline suddenly in the 1950s. The reason was unknown at first, but in any case the sharp decrease in mortality without any active measures was welcomed in the USA as “an unplanned triumph” [1]. It is now clear that the decreasing trend in gastric cancer occurrence paralleled the decrease of Helicobacter pylori infection. This bacterium has inhabited the human stomach since humans left Africa 58,000 years ago [2], but its existence was revealed only recently. Its carcinogenic mechanism has been rigorously investigated in the past 20 years, and as if it were a criminal whose crime had been uncovered, it started to leave the human stomach before an eradication policy was launched.

After an interval following the decline in the occurrence of of H. pylori-related gastric cancer, a new disease entity, lower esophageal adenocarcinoma, appeared and has rapidly increased in frequency together with esophagogastric junction cancer in Western countries. Most Eastern countries still seem to be in the final phase of the interval before the increase in the frequency of these troublesome diseases, and today the difference between East and West in clinical approaches to esophagogastric junction cancer seems to be the largest in history. Asian gastroenterologists and surgeons detect and treat early disease, mostly in the distal part of the stomach, by developing new diagnostic devices and function-preserving treatments. Their Western counterparts, on the other hand, desperately struggle against advanced tumors in the proximal part of the stomach, making full use of a multimodal, multidisciplinary approach. Bridging these two groups is worthwhile and beneficial, especially for the minority populations of patients in each group, but needs mutual understanding based on common points of view. Researchers and pathologists are highly expected to play a role in establishing a common language for these differing practices. Face-to-face meetings and discussions in recognition of the other’s standpoint would be particularly profitable.

We organized the 88th Annual Meeting of the Japanese Gastric Cancer Association in March 2016, setting the congress theme as “Gastric cancer: Asia and the world.” Although this was essentially a domestic meeting, 70% of the sessions were conducted in English, and were attended by more than 2000 physicians and pathologists, including those from 14 countries. This special issue of Gastric Cancer comprises original and review papers presented in the plenary and main sessions of the meeting. It covers a wide range of the latest knowledge from H. pylori to challenging therapy for peritoneal dissemination, with special reference to the difference between Asia and other parts of the world. I cordially thank the authors and reviewers for giving their time for this special issue, and I hope it will help researchers and physicians worldwide in developing insights into gastric cancer.