[Mitotic activity of cancer in the colorectum: correlation with histopathologic variables and survival]

An in vivo stathmokinetic method was used to analyze the mitotic activity (MA) of cancer cells from 43 colorectal cancer patients in order to examine the correlation between MA, and histopathologic variables and survival of patients. Significant relationship was not found between MA and 7 variables of cancer lesions consisting of tumor size, macroscopic type, depth of invasion, venous and lymphatic invasion, node metastasis and stage. However, tumor differentiation was significantly related to MA: mitotic indices (MI, mean +/- S.D.) were 20.7 +/- 8.8% in 37 differentiated adenocarcinomas and 38.2 +/- 8.4% in 6 undifferentiated adenocarcinomas. The latter was significantly (p less than 0.001) higher than the former. The survival curve of 23 patients with low MA (MI less than 20.0%) was significantly (generalized Wilcoxon test, Z = 2.17, p less than 0.05) better than that of 17 patients with high MA (MI greater than 20.0%), though difference in 2 (lymphatic invasion and tumor differentiation) out of 12 variables of background was found between them. The survival curve of 17 patients with differentiated adenocarcinoma of low MA also was significantly (Z = 1.98, p less than 0.05) better than that of 17 patients with differentiated adenocarcinoma of high MA, even though no significant difference of 12 variables in background was found between them. These results suggest that MA of cancer cells may be independent of prognostic variables of cancer lesions and may be utilized as a new prognostic variable of colo-rectal cancer.