Correlation between metastatic site, histological type, and serum tumor markers of gastric carcinoma

Gastric carcinoma is classified into intestinal type carcinoma (IC) and diffuse type carcinoma (DC). Intestinal type carcinoma usually tends to metastasize to the liver and DC to the peritoneal cavity. However, discrepant cases are sometimes seen: IC with peritoneal metastasis or DC with liver metastasis. We studied the relationship between histological type and metastatic site with special reference to these discrepant cases. We also studied the serum tumor markers (carcinoembryonic antigen [CEA] and carbohydrate antigen [CA] 19-9). We studied 124 autopsied specimens of patients who died of gastric carcinoma. The primary tumors were classified as IC or DC. The discrepant cases included 19 DCs with liver metastasis and 19 ICs with peritoneal dissemination. Most discrepant cases focally had histological features in the primary tumor consistent with our main supposition. On the other hand, discrepant foci were seen only very rarely in the primary tumor of cases with the corresponding usual metastatic site. The serum CEA levels of specimens from cases with liver metastases were higher than those without liver metastases. The serum CA 19-9 levels showed no significant correlation with the metastatic site of the carcinoma. In conclusion, in gastric carcinoma (1) the metastatic site was correlated with histological type (2) even in cases showing a discrepant metastatic site, focal areas of the histological type consistent with our main findings could be found in the primary tumor, and (3) serum CEA levels correlated with liver metastasis.