The importance of DNA flow cytometry in node-negative breast cancer.

DNA flow cytometric analysis and conventional clinical factors were compared with disease outcome in 257 patients with node-negative infiltrating ductal carcinoma who had been treated between 1976 and 1983. Median follow-up was 80 months; none of the patients received adjuvant therapy. The relative prognostic importance of clinical variables, ploidy, and S-phase fraction was analyzed by Cox multivariate analysis. Ploidy was analyzable for 198 tumors and did not predict survival. Nuclear grade predicted disease-free survival for all patients. For 71 patients with diploid tumors, only high S-phase had a statistically significant association with relapse. For 127 patients with aneuploid tumors, tumor diameter predicted both disease-free survival and cancer death; histologic grade was also significant for predicting disease-free survival. In conclusion, flow cytometric determination of ploidy and S-phase fraction can provide valuable predictive information in node-negative breast cancer in addition to conventional variables.