RESUMEN
Colorectal carcinoma occurs at a much lower frequency in Egypt than in western countries. In this study of forty colorectal carcinomas we investigated the prognostic value of flow cytometric ploidy and S- phase measurements together with various morphological characteristics of the tumors. Repeated measurements of 324 paraffin - embedded or fresh samples from the 40 tumors demonstrated the high reproducibility of ploidy and S- phase analysis [r=0.97 and r= 0.89 respectively]. Tumor heterogeneity showing diploid and aneuploid cell population or aneuploid cell populations with various ploidy values by measuring a mean of 4.6 samples /tumor was found in 40%, while the proportion of aneuploid tumors increased significantly with grade but not with stage of the tumors. The% S-phase cells correlated with grade but not with the stage. After a follow up of 24 months, in the Kaplan Meire univariate Analysis, the following factors had a prognostic value, staging [P=0.005]. ploidy level [P=0.0018],% S-phase [P=0.0006], histopathological types [P=0.01], grading [P=0.05]. Multivariate Analysis using Cox's proportional Hazanl model revealed independent prognostic value for Dukes' stage [P=0.02], and ploidy level [P=0.05]