[Comparative study on biological difference between gastric cancer and colorectal cancer]

In this study, we investigated the clinico-pathologic characteristics of patients with adenocarcinoma of the stomach and those with colorectal carcinoma to compare early progression patterns of both tumors. Histologically, gastric and colorectal adenocarcinomas showed similar progression patterns, including the incidence of submucosal invasion, lymphatic infiltration and lymph node metastasis. One striking finding was in gross appearance in born tumors. In contrast to most gastric well differentiated adenocarcinoma (DTA), which showed superficial growth, colorectal DTAs mainly showed polypoid growth. However, the superficial-type colorectal DTAs invaded the submucosal layer more frequently than did polypoid DTAs and gastric DTAs. These findings indicate that superficial-type colorectal DTAs grow more rapidly and aggressively than do polypoid DTAs and gastric DTAs. In order to elucidate growth rates between gastric cancer and colorectal cancer with hepatic metastasis doubling time was measured by exponential growth of tumor marker (CEA or AFP). The doubling time of liver metastases calculated from tumor markers was 26.6 +/- 10.8 days for stomach cancer and 57.8 +/- 35.4 days for colorectal cancer; accordingly doubling time for gastric cancer was approximately half of that for colonic cancer. However, there were no other factors (age, sex, site, histologic type in stomach, tumor marker production, etc.) influencing doubling time.