Two-color, cytokeratin-labeled DNA flow cytometric analysis of 332 breast cancers - Lack of prognostic value with 12-year follow-up

Context.-DNA flow cytometry of breast cancer is a proposed tumor marker of prognostic significance that is of controversial clinical utility because o f lack of standardization and confirmatory studies. Objective.-To evaluate the prognostic significance of the more informative technique of multiparametric 2-color DNA flow cytometry as recommended by t he 1992 DNA Cytometry Consensus Conference. Design.-Three hundred thirty-two breast carcinomas with 7 to 12 years of fo llow-up were prospectively analyzed as fresh tumors that were mechanically dissociated into whole cell suspensions. These suspensions were dual fluore scence-labeled with propidium iodide (DNA) and antibodies to cytokeratin (e pithelium) and leukocyte common antigen (internal leukocyte control) for ga ted analysis of subpopulations. Multicycle software with histogram-dependen t algorithms employing background, aggregate, and debris correction were us ed in DNA and cell-cycle quantitation. Data were analyzed according to the DNA Flow Cytometry Consensus Conference recommendations. Results.-DNA ploidy and proliferation stratified into 3 categories were not predictive of overall or disease-free survival. Sixty-five percent of tumo rs were nondiploid, and 35.4% were diploid. Two hundred six tumors were abl e to be evaluated for synthesis-phase fraction (SPF) analysis, with 74 of 2 06 cases in the low range (<13.4%), 36.4% in the intermediate range (>13.5 to <25.4%), and 27.6% in the high SPF (>25.5%) category. Aneuploid tumors t ended to have a higher SPF. Univariate survival analysis showed prognostic significance of the following: tumor size, stage, TNM components, vascular invasion, nuclear grade, and histologic grade. Only T classification, prese nce of positive axillary lymph nodes, and distant metastases were significa nt independent predictors of survival in multivariate Cox regression models . Age and hormone receptor status showed no prognostic significance. Synthe sis-phase fraction was significantly correlated with tumor size, stage, T c lassification, nuclear and histologic grade, presence of estrogen or proges terone receptors, and axillary lymph node status. None of the histologic pa rameters showed any significant association with DNA aneuploidy, except for high nuclear and histologic grade and the absence of estrogen receptors. Conclusions.-Despite the use of state-of-the-art processing and flow cytome try analytic techniques, DNA ploidy and proliferation measurements were not predictive of survival in any stage of breast cancer. However, select hist opathologic parameters and TNM stage were significant predictors of surviva l in univariate and multivariate analyses. We conclude that DNA ploidy and proliferation measurements do not provide significant prognostic informatio n for clinicians to integrate into therapeutic decision making for patients with breast cancer.