Prediction of relapse in patients with breast cancer by DNA cytometry

Nuclear DNA content was quantified for 193 ductal invasive breast carcinomas in a prospective study. The results were correlated with various clinical parameters. Of these tumours 66.2% were non-diploid and the incidence of non-diploid tumours is significantly higher in later stages of the disease. The median DNA values distribution tend to be bimodal, although in stage III a large number of cases showed DNA values between 2C and 4C. No association was observed between ploidy and menopause, lymph node status or incidence of recurrence. The mean times of relapse were 22.4 and 18.8 months in diploid and non-diploid groups, respectively. The present data suggest association between non-diploidy and tumour aggressiveness. Using Bayesian statistical analysis, the probability of the mean time of relapse in diploid group to be longer than in non-diploid group, given the data, is 0.875.