ALTHOUGH the frequency of gastric cancer is decreasing yearly in western countries, it prevails in countries such as Chile, Ireland, and Japan. Most of the cancers diagnosed by routine roentgenologic examinations are advanced, and life-saving surgery, radiotherapy, or chemotherapy hardly are expected for them.
Recent statistical studies show that the five-year survival rate of patients on whom surgical resection of gastric cancer was performed is less than 40%, while that of patients with early gastric cancer is more than 95%. These data strongly emphasize that early detection and early resection can only improve the present poor state of cure from this disease.45
Early gastric cancer, which is defined in Japan as mucosal and submucosal cancer, can be classified into the following three types by gross appearances: I, protruded; II, superficial; and III, ulcerated. The protruded type includes sessile or pedunculated polyps with malignant transformation and polypoid cancer. The superficial