Characteristics of gastric cancer invading to the proper muscle layer--with special reference to mortality and cause of death.

A total of 2,608 patients with gastric cancer received curative or palliative resection in the surgical department of the National Cancer Center Hospital during the 13-year period from 1968 to 1980. Of these, 261 patients with gastric cancer invading to the proper muscle layer (pm cancer) were studied. The incidence of pm cancer was 10.0% (261/2,608). Annual incidence showed a tendency of a little increase as compared with the pronounced increase in early cancer in recent years. Male patients comprised 67% of the total. Sixty- to 69-yr-old patients constituted 28.7%. This cancer occurred more frequently in the lower portion and the lesser curvature of the stomach. The type looking like early cancer comprised 38.3% (100/261). Histologically, undifferentiated types constituted 50% (131/261) and differentiated types comprised 44% (117/261). There were nine patients with distant metastasis despite the fact that the invasion was limited to the pm layer. Eighty-one (31%) of the 261 patients had died by November 1984. However, the survival period was longer than that for advanced cancer invading to the serosal layer. Concerning the cause of death, 48 (59.2%) of the 81 patients died of recurrent cancer and 27 (33.3%) died of nonmalignant disease. Death caused by hematogenous metastasis, especially liver metastasis, was the most characteristic. A close relationship was not found between the mode of invasion to the pm layer and mortality.