A Prospective Evaluation of the Effect of Tumor Cell DNA Content on Recurrence in Colorectal Cancer

Tumor cell DNA (ploidy) content was measured prospectively in samples from 320 patients resected for colorectal cancer with a minimum follow-up time of 2 years. All patients were followed and those with recurrence were investigated carefully. There was no correlation between tumors with an abnormal cellular DNA content (aneuploid or tetraploid) and patient age, sex, tumor site, pathologic stage, or histologic grade. In 236 patients who underwent potentially curative operations, 75 (32%) had local and/or distant recurrence. The recurrence rate was significantly higher (test statistic, 4.3; P = 0.04) for those patients with aneuploid tumors (52 of 142, 37%) compared with those with diploid tumors (23 of 94, 24%). The subgroups of patients where ploidy exerted an effect were in patients with Stage B tumors or mobile tumors and in patients over 65 years of age. Further analysis showed that there was a twofold increase in local recurrence and a threefold increase in distant recurrence in patients with aneuploid tumors, but no excess of patients who had both local and distant recurrence. Measurement of DNA ploidy can identify a group of patients undergoing curative surgery for colorectal cancer at high risk for recurrence. In combination with clinicopathologic factors, DNA ploidy may be useful in analyzing the results of trials and in planning adjuvant therapy. Cancer 67:2599-2604,1991. HE PROGNOSIS for patients with colorectal cancer is T usually determined by assessing the degree of spread of the tumor expressed as the pathologic stage. Dukes’ stage’ with subsequent modification^^.^ remains the standard for judging a patient’s likelihood of long-term survival. Although it is accepted that patients with localized disease and those with distant metastases will tend to have a good or poor prognosis, respectively, there are many patients in an intermediate group for whom the outcome