Changing patterns in gastric adenocarcinoma.

A retrospective study was performed on gastric cancer patients admitted to the Cancer Institute Hospital, Tokyo, during the periods 1961-65 (n = 1181) and 1980-84 (n = 1473). The aim of the study was to see whether changes had occurred in gastric cancer patients over the years with respect to histology and tumour localization and, if so, how they compared with reports from the West. The proportion of proximally localized primary tumour increased from 17 to 27 per cent (P = 0.008), and signet-ring cell carcinoma increased from 2 to 22 per cent (P less than 0.001). These changes were not relative with regard to the declining incidence of intestinal tumours, but absolute. Patients with proximally localized tumours were generally in a more advanced stage of disease than those with distally localized tumours, and thus had poorer survival rates. However, after stratifying into stages, the difference in survival disappeared. The survival rate of patients with signet-ring cell carcinoma was not significantly different from that of patients with other gastric tumours (P greater than 0.05). The discrepancy between the survival rates of Japanese and western gastric cancer patients is attributed by some authors to tumour-related factors. However, we believe that the similar trends found with regard to tumour localization and histology point towards comparable tumour behaviour in the two different geographical areas.