Prognostic implications of proliferative activity and DNA aneuploidy in colonic adenocarcinomas

Paraffin-embedded surgical specimens from 120 patients who underwent resections for primary untreated colonic adenocarcinoma were examined for proliferative activity, DNA aneuploidy, DNA index, and the proportion of aneuploid cells by flow cytometry. The results were correlated with survival times and clinical characteristics of the patients. The presence of metastases, both distant and restricted to local lymph nodes, was found to be a more potent adverse prognostic indicator than any DNA flow cytometry-derived parameter. Additional analyses were performed following stratification of patients into two groups on the basis of presence or absence of metastases. Analysis of 60 patients without metastatic involvement revealed a significant correlation between high proliferative activity, defined as more than 20% of cells in S-phase, and DNA aneuploidy. In fact, high proliferative activity was shown to be a more powerful adverse prognostic indicator in relation to survival than DNA aneuploidy in these cases after multivariate analysis. These results suggest that differences in proliferative activity may be an important biologic factor operative in the variable prognosis seen in colonic adenocarcinoma. In addition, they re-emphasize the importance of stratifying patients into groups based on metastatic involvement when evaluating other possible prognostic features in this disease.