MP COLORECTAL-CANCER SHOULD BE DEFINED AS EARLY COLORECTAL-CANCER

Little is known about the clinicopathologic features of mp colorectal cancer, defined as a cancer where the depth of invasion is limited to within the mucose, the submucosa and the proper muscle. This study mas designed to determine the clinicopathologic features of mp colorectal cancers. From 1973 to 1993, 83 mp colorectal cancer and 66 sm colorec tal cancer patients were treated in our department and were enrolled i n this study. During the same period, 66 patients with sm colorectal c ancer defined as a cancer where the depth of invasion is limited to wi thin the mucose and the submucosa, were treated. The clinicopathologic findings of these patients were determined retrospectively from their hospital records. Clinicopathologic differences in sm and mp colorect al cancers were compared with sm and mp gastric cancers. The incidence of mp colorectal cancer increased from 7.9% in 1973-1977 to 16.2% in 1988-1993. An advanced macroscopic appearance, a larger tumor size: ly mph node metastasis and lymph vessel invasion mere more predominant in mp than sm colorectal cancer. Multivariate analysis demonstrated that these clinicopathologic factors mere not statistically independent pr ognostic factors for mp colorectal cancer patients. There was no stati stical difference in postoperative survival between sm and mp colorect al cancer patients. Mp colorectal cancer should be defined as early co lorectal cancer, because the postoperative survival rate does not diff er between mp and sm colorectal cancers, and the clinicopathologic dif ferences between these two are negligible. (C) 1998 Tohoku University Medical Press.