In Japan, R2 lymph node dissection is standard practice for all curatively resected gastric cancer patients. From 1969 to 1984, data were collected prospectively to evaluate this procedure and to provide information for a more rational approach to node dissection for each individual case. A total of 3843 cases was included in this study and an evaluation was made of the prognostic variables and lymph node involvement at various locations. Using a computer program, it is possible to compile a group of treated patients, with prognostic variables exactly matching those of an individual patient. Analysis of this group can then give an indication of the extent of lymph node dissection required for an individual patient. This paper gives a demonstration of the structure of such a system by means of an example.

As a result of Japanese reports of improved survival of gastric cancer patients after extended lymph node dissection, a study was undertaken to evaluate factors that might influence these results. The influence of staging was evaluated by stratifying 1085 patients of the National Cancer Center of Japan and grouping them according to the three commonly used systems; UICC's old and new TNM systems (fourth edition) and the system of the Japanese Research Society for the study of Gastric Cancer (JRSGC). No survival difference was found between the stages of the three systems, except for stage II, where the new TNM and the JRSGC differed (p < 0.05). In a second analysis, the incidence of the most important prognostic factors for advanced gastric cancer was compared among three institutions: the National Cancer Center Tokyo, Japan (NCC), the University Hospital Erlangen, Germany (UHE) and the University Hospital Maastricht in The Netherlands (UHM). Japanese patients were on average 3 years younger than the German patients and 8 years younger than the Dutch patients, and had a higher proportion of advanced (T4) carcinomas. Male-female distribution, histology, and lymph node invasion were comparable in the three groups. From these data a rather worse prognosis for Japanese advanced gastric cancer patients could be expected. However, the observed 5-year survival rates show a marked advantage for the Japanese patients: 57% (NCC) versus 34% (UHE) and 31% (UHM). The survival difference for stage II patients between the new TNM and the JRSGC staging systems is not sufficient to explain this advantage. This result underlines the importance of the Japanese therapeutic approach.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

The effect of perioperative blood transfusion on the survival rate of patients with gastric cancer was studied. One thousand patients with primary gastric cancer, who had curative surgery performed at the National Cancer Center Hospital in Japan from 1976 to 1981, were studied retrospectively. Overall comparison of transfused (n = 371) versus nontransfused (n = 629) patients by log rank analysis revealed a statistically significant adverse influence of blood transfusion on survival (p = 0.0001). Fifty-seven percent of transfused as compared to 80.8% of nontransfused patients survived for 5 years or more; however, after stratifying patients into stages and applying proportional regression analyses, blood transfusion did not appear to have any effect on prognosis: relative risk ratio, 1.16; p = 0.28. Similarly, comparison of patients transfused with more than 600 cc of blood and those transfused with 600 cc of blood or less revealed no statistical difference in survival time. It is postulated that the possible adverse influence of blood transfusion on the survival of patients with gastric cancer is linked to other prognostic features rather than to the immunologic sequelae of the transfusion itself.