Tumor DNA content in primary and metastatic colorectal carcinoma

We performed this study to determine if tumor DNA content was an independent prognostic indicator in patients with primary tumors or hepatic metastases from colorectal cancer. We analyzed tumor DNA content by flow cytometry from paraffin-embedded specimens in 133 patients. In the 77 patients with primary colorectal cancer who had had "curative" resection, DNA content of the tumor was an independent prognostic indicator in predicting both relapse-free and overall survival. Logistics regression analysis demonstrated that aneuploidy, ie, tumors that exhibited a population of cells with an "abnormal" DNA content, was the single most important variable in predicting both recurrence and death from disease, even more important than stage. However, in 56 patients with hepatic metastases from colorectal cancer, the DNA content of the liver metastases bore no relationship to the patients' survival or their response to therapy. These data suggest that tumor DNA content is an important prognostic indicator in patients with primary colorectal carcinoma but does not reflect the natural history of patients with liver metastases.