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 mucosa, the submucosa and the proper muscle. This study was designed to determine the clinicopathologic features of mp colorectal cancers. From 1973 to 1993, 83 mp colorectal cancer and 66 sm colorectal cancer patients were treated in our department and were enrolled in this study. During the same period, 66 patients with sm colorectal cancer defined as a cancer where the depth of invasion is limited to within the mucosa and the submucosa, were treated. The clinicopathologic findings of these patients were determined retrospectively from their hospital records. Clinicopathologic differences in sm and mp colorectal 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, lymph node metastasis and lymph vessel invasion were more predominant in mp than sm colorectal cancer. Multivariate analysis demonstrated that these clinicopathologic factors were not statistically independent prognostic factors for mp colorectal cancer patients. There was no statistical difference in postoperative survival between sm and mp colorectal cancer patients. Mp colorectal cancer should be defined as early colorectal cancer, because the postoperative survival rate does not differ between mp and sm colorectal cancers, and the clinicopathologic differences between these two are negligible.