[Japanese cancer--retrospective and prospective views--gastric cancer].

Based on gastric cancer subjected to surgical operation over the past thirty-five years (1946-1980) at the Surgical Department of Cancer Institute Hospital, the trend of Japanese gastric cancer is reviewed in respect to its diagnosis, treatment and pathological features. In addition, prospective view in this field is presented. The most outstanding feature observed during the thirty-five years is the increase in incidence of early gastric cancer. The frequency of early gastric cancer among surgically treated gastric cancer was as low as only 2% in 1950s, but increased to 35% in 1980s. In parallel, surgical results of gastric cancer improved from 40% to 64% in terms of 5-year survival rate. It is attributable to the efforts by Japanese Research Society for Gastric Cancer performing extensive overview of the results of gastrectomy and also to the Progress in diagnosis of gastric Cancer. Gastric ulcer and gastric polyp were emphasized in 1950s from the viewpoint of precancerous condition, but from the studies of malignant cycle and borderline lesion--atypical epithelium--it has been proved that gastric ulcer and gastric polyp rarely develop malignant change. At present, gastric ulcer and polyp are considered to be a clue to the discovery of early gastric cancer. Recently, the number of aged patients with gastric cancer have increased remarkably, indicating a serious diagnostic problem in the near future. Further endeavor at early detection of gastric cancer should be made, so that early gastric cancer will be over 50% of operative gastric cancer. The author believes it will lead to overcome gastric cancer.