Chronological Trends in the Pathological Characteristics of Gastric Cancer

1,780 patients have undergone gastrectomy for gastric cancer in our clinic, and the chronological trends in the pathological findings of this cancer have been evaluated. Recently, the proportion of patients with early cancer was markedly increased: from 22.4% in the 1960s to 29.6% in the 1970s and 39.2% in the 1980s. In terms of age distribution, a decrease in the proportion of patients under 50 years of age (27.6,26.4 and 18.4% in the 1960s, 1970s, and 1980s, respectively) and an increase in the proportion of patients over 70 years of age (9.4,16.5 and 22.8% in the 1960s, 1970s and 1980s, respectively) were noticed. The decrease may be related to westernization of dietary habits in Japan after World War II. In terms of pathological findings, macroscopically there was a decrease in the elevated type of early cancer (23.9% in the 1960s, 18.9% in the 1970s and 10.5% in the 1980s) and in the localized type of advanced cancer (36.6, 23.5 and 27.9% in the 1960s, 1970s and 1980s, respectively). Microscopically, there was a decrease in the proportion of the intestinal type, such as papillary adenocarcinoma (from 37.7% in the 1960s to 22.2% in the 1980s in early cancers; and from 18.5% in the 1960s to 13.2% in the 1980s in advanced cancer). Thus, a westernization of the characteristics of gastric cancer was observed, and consequently, in Japan, a reduction in the incidence of gastric cancer is expected. As the rates of resectability and curative resectability have improved, the 5-year survival rate has improved chronologically, with rates of 60.7, 67.6 and 76.7% in the 1960s, 1970s and 1980s, respectively.