T2071 Clinicopathological Time Trends for Early Gastric Cancer and Helicobacter pylori Infection in Japan

Abstract

BACKGROUND: The annual incidence of gastric cancer in Japan continues to increase, while the mortality rate from the disease is leveling off. The infective rate of H. pylori is very high in the Japanese population, but a decreasing trend is observed in younger generations. We investigated the clinicopathological time trends for early gastric cancer in relation to H. pylori infection. METHODS: A comparison of the clinicopathological characteristics, including H. pylori infection, of 383 patients with early gastric cancer treated at the Osaka Medical Center for Cancer and Cardiovascular Diseases from 1980 to 1985 with 528 similar patients treated from 2000 to 2005. RESULTS: Between the groups over two decades, the proportions of male patients and patients older than 60 increased significantly (P<0.01). Macroscopically, the percentage of elevated type cancers increased significantly, while the percentage of depressed type cancers with ulcer, or ulcer scar, decreased ( P<0.01). The percentage of tumors smaller than 30 mm increased (P<0.01). Histologically, the percentage of intestinal type cancers increased, while mixed and diffuse type decreased (P<0.01). The prevalence of H. pylori infection in both time periods was very high (91% and 95%). Many H. pylori negative patients had severe atrophic gastritis and seemed H. pylori pseudonegative. CONCLUSIONS: These trends are thought to reflect the increasing proportion of elderly people in Japanese society, and the decreasing number of H. pylori positive people in younger generations.