5-YEAR PROSPECTIVE-STUDY OF DNA TUMOR PLOIDY AND COLORECTAL-CANCER SURVIVAL

Background. Retrospective studies have suggested that DNA tumor conten t (ploidy) has a significant effect on survival. This group has report ed, prospectively, that among patients who had colorectal resections f or carcinoma, the 2-year tumor recurrence rate was significantly great er for patients with aneuploid tumor than for those with diploid tumor s. This paper reports the 5-year survival rates of this cohort of pati ents. Methods. Three hundred sixty-three patients who had colorectal r esections for cancer between November, 1982, and March, 1988, were stu died prospectively. The DNA tumor ploidy was measured from fresh and p araffin embedded tissues. These patients were followed regularly in a dedicated colorectal clinic for a minimum of 5 years or until death. O f the 363 patients studied, 2 were lost to follow-up. Results. Forty p ercent of the tumors were diploid, the remainder aneuploid, The 5-year survival for patients who had curative resections was 76% for those w ith diploid tumors compared with 64% for aneuploid tumors (P = 0.05; M antel-Cox, 3.7). On further analysis, the survival benefit conferred b y a diploid tumor appeared to be confined to those with Stage B tumors . There was no relation between ploidy and sex, age of patient, stage, histologic grade, or site of tumor. Conclusions. Ploidy is a useful o bjective measurement of the aggressiveness of Stage B tumors. Patients with aneuploid Stage B tumors have a poor prognosis; this group may b enefit from adjuvant therapy.