Background/aims: The significance of prognostic value of DNA ploidy patterns of colorectal cancer has not yet been fully understood. The present study was designed to determine the prognostic value of DNA ploidy patterns for colorectal adenocarcinomas after resection.
Methodology: We have prospectively collected tumor specimens from 420 patients with colorectal cancer since 1996. The DNA ploidy patterns were determined with the use of DNA flow cytometry. The correlation of DNA ploidy pattern and various characteristics of tumors and the prognostic significance of DNA ploidy patterns were evaluated by univariate as well as Cox's proportional hazard model. The disease-free survival curves were calculated with Kaplan-Meier's analysis, and the survival difference was determined by log-rank test.
Results: DNA ploidy patterns were diploid in 115 (27.4%) and aneuploid in 305 patients (72.6%). The pattern of DNA ploidy did not correlate with age, gender, location, differentiation, and stage of the tumors. In 146 patients who were followed up for at least 2 years, the disease-free survival curves were similar between the diploid and aneuploid group. Multivariate analysis disclosed that tumor staging was associated with the survival of patients but the DNA ploidy pattern had no prognostic significance.
Conclusions: The DNA ploidy pattern was not a significant prognostic factor in short-term follow-up.